Contribute WFS 1.1.0 spatial filtering to OWSLib

[Roel]

Since we have (most of the) code to do spatial filtering in WFS 1.1.0 POST GetFeature requests anyway and the standard is not going to change anymore, it makes sense to contribute this upstream to OWSLib next to our efforts of upgrading the pydov/OWSLib stack to WFS 2.0.0.

Again this can/needs to be done in two phases:

• Make sure WFS 1.1.0 GetFeature works via POST next to GET

  • Relates to upstream issue WFS GetFeature via POST geopython/OWSLib#439
  • Can be done after the WFS 2.0.0 POST GetFeature request (see Switch to WFS 2.0.0 #194), to align with that implementation?

• Integrate our locations (GML3.1.1) and location filters (OGC) in OWSLib

  • Relates to upstream issue Implement remaining spatial filters in owslib.fes geopython/OWSLib#128
  • Work can start on this now, I can take the lead on this.

Relates to #194

[pjhaest]

👍