feat: add availability endpoint

[davidgamez]

Summary:

This PR adds the /v1/gtfs_feeds/{id}/availability endpoint, returning GET/HEAD checks for GTFS endpoints.

Expected behavior:

Explain and/or show screenshots for how you expect the pull request to work in your testing (in case other devices exhibit different behavior).

Testing tips:

Using local development:

• Execute

./scripts/init-local-folder.sh
./scripts/docker-localdb-rebuild-data.sh --populate-data --populate-test-data

• Start the api

./scripts/api-start./sh

• Execute the curl command

curl --request GET \
  --url http://localhost:8080/v1/gtfs_feeds/mdb-1/availability

• Verify the response

From our ai friend

This pull request adds support for querying historical availability checks for GTFS feeds via a new API endpoint. It includes the implementation of the endpoint, model mapping, test data population, and comprehensive integration tests to validate filtering, pagination, and error handling.

API and Model Implementation:

• Added a new endpoint get_gtfs_feed_availability to feeds_api_impl.py that returns historical availability checks for a GTFS feed, with support for filtering by date range, sorting, pagination, and error handling for invalid parameters.
• Introduced GtfsFeedAvailabilityCheckImpl to map database ORM objects to API models, including mapping of request_type to HTTP method names.
• Registered new models in the OpenAPI generator file for availability check and response.
• Added a new error message for when the 'from' timestamp is after the 'to' timestamp.

Test Data and Integration Testing:

• Updated test data population script and test data JSON to include GTFS feed availability checks, ensuring the new endpoint has fixture data for testing. [1] [2]
• Added comprehensive integration tests for the new endpoint, covering basic response, ordering, filtering, pagination, and error scenarios.

Imports and Supporting Changes:

• Added necessary imports for new models and implementation classes throughout the codebase. [1] [2] [3] [4] [5]

Please make sure these boxes are checked before submitting your pull request - thanks!

• Run the unit tests with ./scripts/api-tests.sh to make sure you didn't break anything
• Add or update any needed documentation to the repo
• Format the title like "feat: [new feature short description]". Title must follow the Conventional Commit Specification(https://www.conventionalcommits.org/en/v1.0.0/).
• Linked all relevant issues
• Include screenshot(s) showing how this pull request works and fixes the issue(s)

[davidgamez]

This fixes local testing

[cka-y]

LGTM