[Csnd-dev] Supported Platforms

Hi All,

I'm looking at platforms for us to support, mainly using the criteria of
what is supported by the platform maintainers (i.e., MS, Apple, Linux
Distros) for LTS. If the platform maintainers are no longer supporting a
version of an OS, then I think we are okay to drop support for it as well.

The main impact from supporting these older platforms is that we should
look at the version of dependencies they have available. For example,
Debian 10 has CMake 3.13 as its last release available in its repo.

From looking around I think we should support:

* Windows 10 (EOL is Oct 14th, 2025:
https://learn.microsoft.com/en-us/lifecycle/products/windows-10-home-and-pro
)
  * Unsure what version of Visual Studio we should set for support
* macOS 12 (Apple support current and last two versions of macOS:
https://endoflife.date/macos)
* Linux
  * Debian 10 (https://wiki.debian.org/LTS)
  * Fedora 38 (from looking at https://pkgs.org/)
  * Ubuntu 20.04 (https://ubuntu.com/about/release-cycle)
  * OpenSuse 15.4
  * Arch (rolling release)

For architectures, I assume:
* x64 for Windows
* x86_64 + arm64 for macOS
* amd64 and arm64 for Linux

For desktop systems, am I missing anything? If we can finalize the
supported platforms, we can then look at dependencies for versions we
should be using.

For Mobile, we have iOS and Android. I have not kept up with either to know
what platforms are the minimums we should support, but we should also
document and keep those up to date.

For the web, we have some control via Nix for toolchain versioning for
building WASM Csound. There is an open PR for adding back in Emscripten
support that we'll need to resolve. However, I think we'll likely be more
limited by earlier Linux Desktop platforms more than anything in regards to
tools and library versions.

For embedded (e.g., Bela, baremetal, RPi), I'm not on those platforms so I
need suggestions from others for what to add for supported platform
documentation.

Thanks!
Steven