[ENH] Add /pipelines router & route for fetching available pipeline versions

[alyssadai]

• Closes Create new endpoint to return pipeline vers. for specific pipeline name for query tool #344
• See also Refactor generic /attributes router into attribute-specific routers #354

Changes proposed in this pull request:

• Added new router /pipelines with a /{pipeline_term}/versions subpath that returns available versions of a specific pipeline resource
• Renamed existing util for unpacking a response from the graph, for clarity

Checklist

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• PR links to GitHub issue with mention Closes #XXXX
• Tests pass
• Checks pass

For new features:

• Tests have been added

For bug fixes:

• There is at least one test that would fail under the original bug conditions.

[coveralls]

Pull Request Test Coverage Report for Build 11357952549

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

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• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 28 of 28 (100.0%) changed or added relevant lines in 5 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.1%) to 95.641%

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Totals
Change from base Build 11277385309:	0.1%
Covered Lines:	768
Relevant Lines:	803

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💛 - Coveralls

[surchs]

Thanks @alyssadai

left two comments, 🧑‍🍳

[neurobagel-bot]

🚀 PR was released in v0.4.0 🚀