Draft: Add path locking to the GraphQL blob API

What does this MR do?

Path locks are an EE feature that needs exposing for the reimplementation of the repository view, per #323195 (closed)

This code is extracted out of !58906 (merged) but does not depend on it. There are some N+1 issues that we need to resolve to make these fields available efficiently.

Should the endpoint for this be blobs at all? Perhaps a separate path_locks field would be better?

Screenshots (strongly suggested)

Does this MR meet the acceptance criteria?

Conformity

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  • I have included a changelog entry.
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• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
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Security

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Related to #323195 (closed)