Draft: Update Rich/RichMirrorAlignmentOnline for use during Run 3 (RICH-51, RICH-60)

This branch contains updates to the package Rich/RichMirrorAlignmentOnline.

This is to prepare the package for use during LHCb Run 3.

Rich/RichMirrorAlignmentOnline/files/XML_YAML_config/README.md

+# XML <-> YAML conversion tool
+## Introduction
+
+The XML YAML conversions tool allows for quick conversions between XML and YAML.
+This tool will take any XML or YAML file and output the data in the same location 
+with the same filename, but the opposite file type. 
+
+The conversion tool supports additional features:
+* A blocklist of items that should not be included in the output file
+* A conversion table for converting parameter names and units between file types
+* A numerical unit conversions table for numerical conversions between units
+* A custom yaml parser that allows the converter to parse custom yaml tags
+
+
+**WARNING:** Do not parse or convert YAML files from untrusted sources. The 
+parser used in this tool has the ability to construct arbitrary python objects 
+which may be harmful.
+## REQUIREMENTS
+The tool requires a working version of Python 3 with additional modules:
+* PyYaml
+* lxml
+* numpy version 1.21.0 or later
+## CONFIGURATION
+The blocklist, conversion table, unit conversions table, and custom yaml parser
+can be configured through the text files in "Configuration_files".
+### Conversion Tool
+Conversion is a python object that handles all file conversions between XML and
+
+YAML. The object is initiated as a class instance and can then be used to make 
+any necessary conversions. A XML <-> YAML conversions are run by calling 
+"conv_XML" and "conv_YAML" respectively and passing the relevant file path (see 
+examples below).
+
+**Note:** Conversion requires the user to add the absolute path to the directory 
+"Configuration_files" on line 5 in "convert_XML_YAML.py" prior to any use.
+#### Examples
+
+The conversions tool may be initiated under the variable "conversion_variable":
+
+    conversions_variable = conversions()
+
+To convert an XML file to YAML the absolute file path is passed to the conv_XML:
+
+    conversions_variable.conv_XML(r"absolute_path_to_file_dir/filename.xml")
+
+This results in the file "absolute_path_to_file_dir/filename.yml" being created.
+
+To convert a YAML file to XML the absolute file path is passed to conv_YAML:
+
+    conversions_variable.conv_YAML(r"absolute_path_to_file_dir/filename.yml")
+
+### Blocklist
+The blocklist is a list of illegal node names that will be blocked when 
+converting. It is configured through the file "blocklist_config.txt" which 
+contains a list of names to ignore. Each new line in the document denotes a new 
+illegal node name, node beginning, node ending or node wildcard. Illegal node names are denoted 
+by typing in the full node name. Illegal node beginnings are denoted by typing in 
+the beginning followed by a "-". Illegal node endings are denoted by typing in 
+the ending and adding a "-" to the front of it. Illegal node wildcards are denoted by typing in a "*" 
+followed by the wildcard (if the node contains the wildcard string, the node will be removed). ```blisted_write_file``` can be set to ```True``` or ```False``` to write blocklisted conditions to file when converting from xml->yaml (to be added back when converting back to xml). ```reAdd_blocklisted_conditions``` can be set to ```True``` or ```False``` to re-add xml conditions which were removed when converting from xml->yaml (created with ```blisted_write_file = True```).  
+
+
+
+**Note:** All node names are case sensitive and "-" ("*") is an illegal character in a
+node name because it is used to define beginnings and endings (wildcards).
+#### Examples
+
+* "and" will block "and" but not "hand", "andrew", or "And"
+
+* "and-" will block "and" and "andrew" but not "hand" or "And"
+
+* "-and" will block "and" and "hand" but not "andrew" or "And"
+
+* "*and" will block "and" and "hand" but not "And"
+
+### Parameter and Unit conversions
+The param_conversion_config.txt file contains translations for parameter names 
+and units between XML and YAML. Each line is defines a set containing the 
+parameter name in XML followed by a ":", then the base unit of that parameter in 
+XML followed by a ":", then the corresponding parameter in YAML followed by a 
+":", and finally the base unit of that parameter in YAML followed by a ":". 
+Everything after the 4th ":" on that line is ignored.
+
+**Note:** If the values in the XML file have specified units when converting XML 
+-> YAML then this will be used instead of the XML base unit.
+### Numerical Unit Conversions
+The unit_conversions_config.txt file contains the numerical conversions between
+units. Each line contains the a unit symbol followed by a ":" then the dimensions 
+of the unit in base SI units followed by a ":" then the value of the unit 
+relative to its base unit followed by a ":". Everything after the 3rd ":" is 
+ignored.
+
+**Note:** all unit names and SI unit names are case sensitive and whitespace is
+NOT ignored. If complex units with more than one base SI unit are used then
+make sure that compatible units have IDENTICAL base units.
+#### Examples
+* "mrad:rad:0.001:" a milliradian has its base in radians and is 0.001 radians
+* "rad:rad:1.0:" a radian has its base in radians and is 1.0 radians
+* "N:kg\*m\*s^2:1.0:" a newton has its base in kg*m*s^2 and is 1.0 kg*m*s^2
+    * Note: "kg\*m\*s^2" will be interpreted differently from "kg m s^2" and 
+    "kg\*m\*s\*s" as compatible base units must be identical.
+### Custom YAML parser and tags
+The custom_tags.txt file contains a list of custom tags used in the YAML
+files where each line contains a single custom tag.
+
+**Note:** The YAML parser will only work if all custom tags are added. 
+
+### Tacking on (or off) extra lines of text
+The ```tack_on_off``` function in ```objects.py``` prepends or appends (or removes) text to the start or end of the file. These lines are manually added in yaml_tack_on_Rich_X.txt or xml_tack_on_Rich_X.txt (where X = 1 or 2), stored in the Configuration folder (defined in ```config_path```). Setting ```tack_on == True``` tacks on the lines and setting ```tack_on == False``` removes the lines.
+        
+* Everything below ```'---top'``` (and above ```'---bottom'```) will be prepended to the top of the file (or removed, if ```tack_on == False```).
+* Everything below ```'---bottom'``` will be appended to the bottom of the file (or removed, if ```tack_on == False```).
+