[WIP] Use Visual Studio and CMake in Windows CI builds

[tautschnig]

With CMake we can actually build natively on Windows/Visual Studio, there should
not be any need for Cygwin.

This is early testing, the PR will remain a draft until all issues are ironed out.

• Each commit message has a non-empty body, explaining why the change was made.
• n/a Methods or procedures I have added are documented, following the guidelines provided in CODING_STANDARD.md.
• The feature or user visible behaviour I have added or modified has been documented in the User Guide in doc/cprover-manual/
• Regression or unit tests are included, or existing tests cover the modified code (in this case I have detailed which ones those are in the commit message).
• n/a My commit message includes data points confirming performance improvements (if claimed).
• My PR is restricted to a single feature or bugfix.
• n/a White-space or formatting changes outside the feature-related changed lines are in commits of their own.

[karkhaz]

It looks like you're doing CI work, but please don't hesitate to ping me if there are any local things you'd like me to try out

[kroening]

Could you actually get rid of cygwin for the build?
This page may be helpful as roadmap:
https://devblogs.microsoft.com/cppblog/cmake-support-in-visual-studio/

[tautschnig]

Could you actually get rid of cygwin for the build?

Given @karkhaz experience it should definitively be possible. I'm just trying to figure out how to do this in CodeBuild.

[tautschnig]

#5162 actually made this happen, closing.