Entrypoint filtering for configuration and deployment APIs

[mmarchetti]

Intent

This PR adds a new entrypoint query parameter to the GET /api/configurations and GET /api/deployments endpoints. Only configurations with a matching entrypoint (or deployments whose configuration has a matching entrypoint) will be returned.

Part of #1847

Type of Change

• • [ ] Bug Fix
• • [x] New Feature
• • [ ] Breaking Change
• • [ ] Documentation
• • [ ] Refactor
• • [ ] Tooling

Automated Tests

Added unit tests specific to the new parameter.

Directions for Reviewers

Test with curl:

$(just executable-path) ui -vv --listen=localhost:9001 &
curl -s 'localhost:9001/api/configurations?dir=test/sample-content/rmd-static-1&entrypoint=static.Rmd'|jq
curl -s 'localhost:9001/api/configurations?dir=test/sample-content/rmd-static-1&entrypoint=index.htm'|jq