Draft: Introduction of RICH Detailed digitization in DD4HEP framework

This is the first version of the RICH detailed digitization in DD4HEP based framework. This needs a recent version of the lhcb-conditions-database where couple of ‘conditions files’ are already merged into couple of simulation branches (MR !114 (merged) or MR !116 (merged)) . This also needs an update in the 'Detector' which activates the use of these conditions which is in Detector MR !472 (merged). The current version is meant to be used for RUN3 digitization. Examples of options files to run this and logfiles obtained will be provided in the comments below, if needed.