OGC API: add support for collection level transactions

[tomkralidis]

Note that tests are not implemented due to lack of public OGC APIs with this capability enabled.

[tomkralidis]

CI failure is intermittent.

[geographika]

@tomkralidis - yes, the intermittent failures relying on external services are a pain point in the project. Might be worth considering making the integration tests only run on demand rather than pull requests and/or consider a local test server returning the same content as the external services using something like https://pytest-httpserver.readthedocs.io

[tomkralidis]

@tomkralidis - yes, the intermittent failures relying on external services are a pain point in the project. Might be worth considering making the integration tests only run on demand rather than pull requests and/or consider a local test server returning the same content as the external services using something like https://pytest-httpserver.readthedocs.io

Neat idea -- can you do a (very small) proof of concept?