Fix bbox crs for OAMaps

[C-Loftus]

Overview

This PR fixes the wms_facade map provider and (OAMaps in general) to project the bbox properly.

• Previously the bbox was being projected with the crs param and not the bbox-crs param. This PR makes the bbox-crs apply to the bbox.
• Moved the projection code to use transform_bbox and moved it into the map API code instead of the provider. This is since all map providers presumably should support projecting the bbox arg
• Added a bbox-crs arg for the wms_facade provider since we have to check if the crs is 4326 when checking whether or not to switch the lat/lon (unusual WMS quirk)
• Added tests for wms_facade since it previously did not have any

Related Issue / discussion

Fixes #1995

Additional information

Dependency policy (RFC2)

• I have ensured that this PR meets RFC2 requirements

Updates to public demo

• I have ensured that breaking changes to the pygeoapi master demo server have been addressed
  • https://github.com/geopython/demo.pygeoapi.io/blob/master/services/pygeoapi_master/local.config.yml

Contributions and licensing

(as per https://github.com/geopython/pygeoapi/blob/master/CONTRIBUTING.md#contributions-and-licensing)

• I'd like to contribute [feature X|bugfix Y|docs|something else] to pygeoapi. I confirm that my contributions to pygeoapi will be compatible with the pygeoapi license guidelines at the time of contribution
• I have already previously agreed to the pygeoapi Contributions and Licensing Guidelines