DecayTreeTuple configuration class

Output designed to be parsed by https://gitlab.cern.ch/admorris/analysishelpers

the workflow I had in mind is something like this:

• create a DTTConfig object with:
  • decay descriptor (from stripping line)
  • branches dict (allows the user to "rename" particles, i.e. choose the prefixes for the columns in the eventual data)
  • input TES location (from stripping line)
  • name (user-chosen)
• render the decay tree as connected nodes
• render the list of TupleTools on each node (including "globally"), obtained from listTools
• add and remove tools as desired with addTool and removeTool. when adding tools, a name is optional but strongly recommended
• configure tools:
  • grab the existing configuration with getToolConfig
  • allow the user to modify it (each option should be an <input> of the appropriate type, checkbox, number, text...)
  • save the changes with configureTool
• at the end, save this.config somewhere (eventually to a JSON file)