[mapguide-internals] Merging RFC 185 work into trunk

[Jackie Ng]

Another update on this.

The SWIG binding work has been merged and trunk is now fully end-to-end
buildable again.

You will now need an installation of SWIG 4.1 as a build pre-requisite. For
convenience, you can get a precompiled windows build of SWIG here:

https://download.osgeo.org/mapguide/support/swig.zip

Unzip this to your C: drive and swig.exe should be under the following
directory structure

   - C:\
      - swig
         - bin
            - Lib
            - swig.exe

The setenvironment64.bat will look for SWIG in this location by default. If
you have SWIG installed elsewhere, you will have to set a SWIG_DIR
environment variable that points to the directory where swig.exe is present.

- Jackie