Add support for non-EPSG projections for WCS and WFS protocols

[geographika]

This pull request adds support for using non-EPSG projection codes in WCS and WFS services. This includes both accessing the data in a non-EPSG projection and advertising the projections in GetCapabilities requests. For example the wcs_custom_projection_capabilities201.xml response includes:

  <crs:CrsMetadata>
    <crs:crsSupported>http://www.opengis.net/def/crs/ESRI/0/54052</crs:crsSupported>
    <crs:crsSupported>http://www.opengis.net/def/crs/EPSG/0/4326</crs:crsSupported>
    <crs:crsSupported>http://www.opengis.net/def/crs/ESRI/0/53009</crs:crsSupported>
    <crs:crsSupported>http://www.opengis.net/def/crs/epsg2/0/42304</crs:crsSupported>
  </crs:CrsMetadata>

And any of these projections can be used to request a coverage e.g. &SERVICE=WCS&VERSION=2.0.1&REQUEST=GetCoverage&COVERAGEID=test&SUBSETTINGCRS=urn:ogc:def:crs:ESRI::53009&SUBSET=x(-3276599.0027238373,-3258457.2498260457)&SUBSET=y(8498088.094072288,8507095.190921152)&SCALESIZE=x(512),y(254)&OUTPUTCRS=urn:ogc:def:crs:ESRI::53009&FORMAT=image/png

A full test suite for WCS 1.0.0, 1.1.1, and 2.0.1 is added in wcs_custom_projection.map.

As several functions were shared with the WFS code, WFS was also updated, and a full test suite found in wfs_custom_projection.map.

WMS had already been updated to handle custom CRSs in #6795.

Note - OGC Features API was not updated, and does not support handling non-EPSG projections. This can be dealt with in a subsequent PR.

Other notes:

• The majority of code changes were to msLoadProjectionString - which is used by several MapServer service protocols.
• The various projection formats which can be handled by the updated are tested in a new Python MapScript test file msautotest/mspython/test_projections.py. In summary any code in the format AUTH:CODE that is in proj.db will be handled, and any authorities not in proj.db can be added using init=CUSTOMAUTH:CODE and search PROJ_DATA for a file with a Proj string.
• This PR fixed a few existing tests which used the newer EPSG:3857 rather than init=EPSG:3857, removing CRS warnings in WMS GetCapabilities

This PR fixes the following issues:

• Advertised ESRI:XXXX projection codes fail in WMS #7231 - Advertised ESRI:XXXX projection codes fail in WMS
• Custom projections not supported via WFS #6981 - Custom projections not supported via WFS

[rouault]

we should likely have a special case to turn "http://www.opengis.net/def/crs/IAU_2015/0/code" as "http://www.opengis.net/def/crs/IAU/2015/code".
The IAU_2015 authority is a bit of a hack, that captures both the authority and version

[geographika]

I'll look at the IAU_2015 again when adding tests for the OGC Features API and non-ESPG projections. I was trying (and not really succeeding!) in keeping the scope of this PR to a minimum. It would be nice to get a lunar Mapfile working as a MapServer demo.

[rouault]

Nice work!

[geographika]

Thanks for the review @rouault - much appreciated!
Having gone through lots of the projection code I think there are quite a few changes it would be good to add as part of a MapServer 9.0, including a requirement for PROJ9+. In addition:

• try and get rid of the custom MapServer +epsgaxis=ne parmaeter and use PROJ to get axis order
• review and update all the references to init= checks in the codebase