Build Rnote and Installer for Windows Arm64

[OB0NE]

Following @Doublonmousse 's advice in #1209 ,I made some adjustments to the former request #1209 to add support for building Rnote on Windows ARM64 while not breaking the x86 build process. architecture. The changes include:

1. Added a new Meson option 'win-arm64-build-environment-path' in meson_options.txt to specify the path for the ARM64 build environment. I also changed the meson.build to detect architecture and chose build environment accordingly.

2. Modified cargo_build.py to detect the system architecture and set appropriate Rust flags:

   • Added platform detection for Windows ARM64.
   • Set '-C linker=clang' flag for ARM64 builds on Windows.

3. Updated rnote_inno.iss.in to include ARM64 architecture support for the Windows installer.

And the issue about black borders is fixed. See https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/7692.

I’ve only been able to test the build on a Microsoft Surface Pro 11, so I'm unsure how it will perform on other ARM devices.