NO TICKET: near-universal adoption of release_status and created_at | complete implementation of active_location for the /thing router | async coverage for all endpoints

[jacob-a-brown]

Why

This PR addresses the following problem / context:

• All responses should have the created_at field
• All responses, except for those from the /lexicon router, should have a release_status field
• All POST requests, except for those for the /lexicon router, should require release_status to be filled
• All PATCH requests, except for those for the /lexicon router, should allow release_status to be edited
• All responses from the /thing router should include an active_location field
• All endpoints should be async

How

Implementation summary - the following was changed / added / removed:

• Added ReleaseMixin to all database models where it was previously absent, except for Lexicon models
• Created BaseCreateModel, BaseUpdateModel, and BaseResponseModel in /schemas/__init__.py to enable universal fields to be present for all relevant models
• updated tests for id, created_at, and release_status where appropriate
• updated tests/test_thing.py for active_location

Notes

Any special considerations, workarounds, or follow-up work to note?

• create_contact was made more flexible for future model/schema changes

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.

Files with missing lines	Coverage Δ
api/contact.py	95.79% <100.00%> (ø)
api/group.py	100.00% <100.00%> (ø)
api/lexicon.py	98.82% <100.00%> (ø)
api/location.py	92.30% <100.00%> (ø)
api/observation.py	100.00% <100.00%> (ø)
api/sample.py	100.00% <100.00%> (ø)
api/search.py	97.77% <100.00%> (ø)
api/sensor.py	77.77% <100.00%> (ø)
api/thing.py	98.43% <100.00%> (+0.02%)	⬆️
db/asset.py	100.00% <100.00%> (ø)
... and 25 more