normalize all feature/record CQL filtering to CQL2 using pygeofilter

[tomkralidis]

Overview

This PR normalizes all feature/record CQL filtering to use CQL2 exclusively (per OGC API - Features - Part 3) using pygeofilter.

Note that this means pygeoapi exclusively supports CQL2 (JSON and text).

Related Issue / discussion

#1557

Additional information

This PR depends on the following:

• PR in pygeofilter: add support for OpenSearch backend pygeofilter#111
• new pygeofilter release required

cc @KoalaGeo

Note that documentation will need to be updated. I'm also triaging this to 0.20 (so in scope once we release 0.19).

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