Build2Client - JobSpec obtain & remove functions

[misterbrunet]

…build2 client

Summary

Adding two more function to the Build2Client:

• api_get_jobspec_for_dataset - retrieves complete JobSpec information for a given dataset_rid and branch
• api_remove_jobspecs - removes JobSpec information for a list of RIDs called jobspec_rids

The logic has been tested directly on Foundry's environment.

Checklist

• You agree with our CLA
• Included tests (or is not applicable).
• Updated documentation (or is not applicable).
• Used pre-commit hooks to format and lint the code.