siibra integration: analysis and API proposal

We have some resources here:

https://github.com/FZJ-INM1-BDA/siibra-explorer

https://siibra-python.readthedocs.io/en/latest/

https://github.com/FZJ-INM1-BDA/siibra-tutorials/blob/main/05-CombinedWorkflow.ipynb

https://github.com/dickscheid/siibra-tutorials/pull/1 

Also few links in the description & comments of the parent task TVB-2980.

Steps would be:

• scan through these links to understand the context
• continue the analysis on this task by proposing how we can query EBRAINS KG through siibra API to retrieve a Connectivity Measure DT into TVB (having a Connectivity from TVB as limit also - the atlas/regions in it are important)
  • the ipynb in PR #1 from Paula https://github.com/dickscheid/siibra-tutorials/pull/1  is a first attempt to have such a feature extracted
• based on the analysis - propose an API/GUI specific to TVB for this CM extraction from KG