improve the MS Windows build script

[totaam]

Let's rewrite it in Python to make it more readable and manageable.

This will also help with SBOM (#4050).

See also #2400 and #3941.

[totaam]

Much better, the output is also much more readable.
Most subcommands send their output to a dedicated log file.
More diagnostics can be included using the --verbose command line switch.

$ python3.11 ./packaging/MSWindows/BUILD.py --no-msi --no-zip --no-installer
* 00:16:26 Collecting version information
    Python 3.11.10 (main, Sep 10 2024, 13:02:13)  [GCC 14.2.0 64 bit (AMD64)]
    Xpra-Light 6.3-r36787
    using 4 cpus
* 00:16:31 locating `signtool`
* 00:16:31 Cleaning output directories and generated files
* 00:16:34 Building Cython modules
* 00:17:24 Generating installation directory
* 00:18:57 Fixups: paths, etc
* 00:18:59 Fixup GStreamer
* 00:18:59 Fixup DLLs
* 00:19:35 Deleting unnecessary DLLs
* 00:19:35 Removing unnecessary Python modules
* 00:19:35 Removing unnecessary files
* 00:19:39 Removing unnecessary PIL plugins
* 00:19:39 Removing empty directories
* 00:19:40 cuda: False
* 00:19:40 numpy: False
* 00:19:40 zipping up some Python modules
Warning: glob 'lib/pynvml' did not match any files!
* 00:19:45 Deleting unnecessary `share/` files
Warning: glob 'share/gst-plugin-base' did not match any files!
Warning: glob 'qt.conf' did not match any files!
* 00:19:46 Removing empty icon directories
* 00:19:46 Adding EXE manifests
* 00:19:46 Generating gdk pixbuf loaders cache
* 00:19:46 Generating icons and theme cache

We can also run the build script against different python versions on the same system, ie:
python3.12 ./packaging/MSWindows/BUILD.py (currently failing for unknown reasons)
python3.11 ./packaging/MSWindows/BUILD.py

The packaging script now also adds its own settings to xpra/build_info.py:

And the size is comparable to the bash version:

# bash:
73	Xpra-Light-x86_64_6.2.0-r0.zip
51	Xpra-Light-x86_64_Setup_6.2.0-r0.exe
211	Xpra-x86_64_6.2.0-r3.zip
151	Xpra-x86_64_Setup_6.2.0-r3.exe
# python:
75	Xpra-Light-x86_64_6.3-r36792.zip
52	Xpra-Light-x86_64_Setup_6.3-r36792.exe
206	Xpra-x86_64_6.3-r36792.zip
146	Xpra-x86_64_Setup_6.3-r36792.exe

Closing, next step is to add the SBOM structured data (#4050).