deegree OGC API shall support OGC API Features - Part 3 - Filtering

[tfr42]

Is your feature request related to a problem? Please describe.
deegree OGC API is not implementing OGC API Features - Part 3 - Filtering : https://docs.ogc.org/is/19-079r2/19-079r2.html

Describe the solution you'd like
deegree OGC API is providing an implementation of Part 3 - Filtering with support for filter in HTML encoding.

Describe alternatives you've considered
none

Additional context
none

[tfr42]

With PR #118 there is a partly implementation for Part 3 - Filtering, limited to CQL2 text function S_INTERSECTS available.

[tfr42]

With PR #150 the support for CQL2 function T_AFTER was added.