Windows: compile xz with CMake

[nulano]

Changes proposed in this pull request:

• Compile liblzma with CMake instead of VS project file, for Updated xz to 5.4.1 #6883 (comment):

  Updated windows/INSTALL-MSVC.txt to mention that CMake-based build is now the preferred method with Visual Studio. The project files will probably be removed after 5.4.x releases.

  This might also help with Failed to build Windows ARM64 dependencies #6679 (comment)

• Use Ninja instead of NMake to build dependencies by default. Unlike NMake, Ninja can build several files in parallel. This makes very little difference on GHA which only provides 2 CPU cores, but is almost 2x faster on my computer.

• Rewrite argument parsing in winbuild\build_prepare.py using argparse for better maintainability.

[hugovk]

• Use Ninja instead of NMake to build dependencies by default. Unlike NMake, Ninja can build several files in parallel. This makes very little difference on GHA which only provides 2 CPU cores, but is much faster on my computer.

Sounds good! What sort of speedup do you see?

[nulano]

Sounds good! What sort of speedup do you see?

Almost 2x on my 6 core 12 thread CPU.

With --nmake:

Days              : 0
Hours             : 0
Minutes           : 6
Seconds           : 44
Milliseconds      : 37
Ticks             : 4040372902
TotalDays         : 0.00467635752546296
TotalHours        : 0.112232580611111
TotalMinutes      : 6.73395483666667
TotalSeconds      : 404.0372902
TotalMilliseconds : 404037.2902

Without --nmake (i.e. with Ninja):

Days              : 0
Hours             : 0
Minutes           : 3
Seconds           : 39
Milliseconds      : 489
Ticks             : 2194899729
TotalDays         : 0.00254039320486111
TotalHours        : 0.0609694369166667
TotalMinutes      : 3.658166215
TotalSeconds      : 219.4899729
TotalMilliseconds : 219489.9729

[nulano]

I originally updated the documentation in this PR to require CMake 3.13+ as that is what xz's CMake files specify.

I missed that the cmake --build command requires CMake 3.15+ when there are multiple targets, I've now updated the PR.

The previous CMake requirement was 3.12, which is what is included with VS2017 and was the oldest I tested when writing the documentation in #4495.

VS2019 includes CMake 3.20, but I've found that 3.15 is sufficient for this PR.