Migrate MSVC checks from AppVeyor to GitHub Actions

[cjee21]

No description provided.

[JeromeMartinez]

@cjee21 I just removed the Appveyor hook in the project settings, please force push with a slight modification e.g. last commit date for forcing the CI to run again.

[JeromeMartinez]

"warnaserror" is good but a bit early :-p, I am working right now on removing the warnings.

[JeromeMartinez]

@cjee21 please rebase.

[JeromeMartinez]

With #2196 we'll be with all on GitHub and all warnings from all compilers caught.

[cjee21]

all warnings from all compilers caught.

But take note that MSVC MediaInfoLib is still on level 1 warnings. The other projects are at level 3 or 4. Last I checked, even increasing to level 2 produces a number of warnings.

[JeromeMartinez]

Last I checked, even increasing to level 2 produces a number of warnings.

True, but remaining issues with level 2 after my pass today are only possible loss of data due to conversions, I'll manage that... but not this week.
GCC and LLVM use the default warnings.