Disable additional MSVC warnings

[donny-dont]

Append additional MSVC warnings to MSVC_DISABLED_WARNINGS_LIST.

[donny-dont]

Attempting to land https://github.com/microsoft/vcpkg/blob/master/ports/libressl/0002-suppress-msvc-warnings.patch into this repository so I ran through the warnings generated for 4.0.0+ code.

[botovq]

Most of these are fine with me, but I would really like to see the output of a build that shows some of these warnings.

Edit: Never mind. I see them in our CI.

[donny-dont]

Can squash this whenever you're done with your review @botovq . Thanks for the speedy replies!

[botovq]

I think I am done. The "'void' function returning a value" will be fixed upstream so it isn't needed. The potentially uninitialized and dead code warnings should only be set on the mentioned files, if it's not too much trouble. Feel free to squash and force push a new version.

[donny-dont]

Ok think I got everything @botovq

If you all decide to do this in the code by pushing and popping warnings then you can drop all the set_source_files_properties changes in this patch.

[botovq]

Thanks. Pushing and popping warnings in a portable way is also ugly, so we'd need to carry patches. I think we're good with this solution for now. If it's getting too unwieldy we can reconsider.

The last sync I just pushed also contains a fix for the 'void' function warning.

[donny-dont]

Great thanks again @botovq !