Add support to export to/convert to .gpkg.zip files

[theroggy]

Feature description

Since GDAL 3.7, support to read and write (not update) .gpkg.zip files was added, using the performance-optimized sozip compression profile:
https://gdal.org/en/stable/drivers/vector/gpkg.html#compressed-files

It doesn't seem possible though to export or convert a file to .gpkg.zip from QGIS though:

• When rightclick/"export"/"save features as..." is used on a layer and "Geopackage is choosen as output, it is not possible to choose .gpkg.zip as extension. If you change the filename to remove the extra .gpkg that is added, this results in an error and no it is still an unzippend .gpkg that is written:
  
• In the "processing toolbox", there is a tool called "GDAL"/"Vector Conversion"/"Convert format", but also there it seems impossible to convert a file to .gpkg.zip.

Opening a .gpkg.zip file does work, though it would be cleaner if .gpkg.zip would also be listed under the "Geopackage" file extensions besides the currently listed ".gpkg and .GPKG".

Additional context

Tested in QGIS 3.34