Integration of the existing FSL parser + update of the action for calculating the nidm examples on the 2 parsers

[thomasbtnfr]

This pull request adds the existing FSL parser and updates the Github action which now computes nidm examples in bids-prov format from the 2 parsers (SPM + FSL).

Question:

• Should we update @context of FSL to align with SPM?
  • FSL : "https://raw.githubusercontent.com/cmaumet/BIDS-prov/context-type-indexing/context.json"
  • SPM : "https://raw.githubusercontent.com/bids-standard/BEP028_BIDSprov/master/context.json"

For the next steps, I think I will be able to make the same modifications as those made to SPM (uuid, mapping for example) if the current outputs are already correct and I can work on boutiques.

[cmaumet]

@thomasbtnfr: To answer your question above: you are right the FSL examples should use the same context as SPM (but if I am correct you have already implemented this).

[thomasbtnfr]

The changes have been made. For the context, in this PR, it's ok for the results of the github action but not for the script in general. This is fixed in the following PR #87