CMakePresets should be able to specify a VC toolset by version number

[sfreed141]

This change addresses item #1965

This changes VS installation detection logic for CMakePresets

The following changes are proposed:

• Update CMakePresets to treat toolset.version to be interpreted as the msvc toolset version, not visual studio version. This is a breaking change but it is the correct interpretation. The latest VS version that matches the requested toolset version and host/target architecture will be used.
• Respect CMAKE_GENERATOR_INSTANCE as of CMake 3.22 and use that when specified in "cacheVariables" (CMAKE_GENERATOR_INSTANCE only applies when using VS generators).
• Remove the reliance on kits for sourcing development environment with presets (now presets will query vswhere.exe and run vcvars*.bat itself).

Notes

• If CMAKE_GENERATOR_INSTANCE is set in a toolchain file we will not respect it. This may or may not cause problems but this is the existing behavior anyways. Simple workaround would be to launch vscode from the desired developer prompt.
• If CMAKE_GENERATOR_INSTANCE isn't found we can still try to find a valid VS instance to use, however CMake will likely throw an error if it can't find the instance either. I considered setting this after we find our instance (and overriding any that the user supplies) but I don't think modifying the preset isn't very user friendly (and it wouldn't address the next caveat with toolchain files). If anything we could provide a toast asking the user for input here but I'll leave that for a future PR.
• Might be worthwhile to cache the results from vswhere.exe and vcvars*.bat, but it didn't seem that bad on my machine (with several VS instances installed).
• I'm not sure how cmake.exe is chosen but it doesn't come from the selected instance that presets will use. This is outside the scope of this PR but it might be nice to make that consistent.

[bobbrow]

• Might be worthwhile to cache the results from vswhere.exe and vcvars*.bat, but it didn't seem that bad on my machine (with several VS instances installed).

We should already be caching the vswhere results. The cache expires after a certain amount of time, but it's there.

[xisui-MSFT]

LGTM

[bobbrow]

We will test this and then merge. There was one comment about the version comparisons, but otherwise, this looks good.