Fix verification cases to qgis2fds 2.0

[johodges]

• Add wcs download algorithm
• Small updates to terrain and fds export for qgis2fds 2.0 algorithm
• Update verification cases to run with new algorithm (also update the remote verification case to download the WCS data first then run the export)

Note that the verification is now embedded in this repository rather than through a separate repo. On my machines I typically use this process to check changes:

• Open an ogr2ogr shell (windows only)
• Run the verification script though qgis-ltr (QGS 3.28) using the command "qgis-ltr --code verify.py". This will result in QGIS opening and running several project files. Upon successful completion, QGIS will automatically close.
• Run the evaluate.sh script. This will run fds and smv for each case in series to allow a manual inspection of the generated geom.

[emanuelegissi]

Great job!

I am just going to do some renaming according to my (unwritten) rules.

[johodges]

Great, and thanks. Could we hold off on the renaming until we get the next PR in? I am just about ready to merge a first cut of github actions on the verification side.