Msvc modular stdlib

[TheRustifyer]

This PR brings finally the official way of using import std and import std.compat by compiling the std modularized libraries on the host project, according to the C++ standard documented in this paper

Most notorious changes (summary):

• import std and import std.compat enabled for all MSVC versions > 19.7
• vsvars are now cached, and parsed beforehand, so we can wire them into shell
• We can finally get rid out of the invokation of the MS devs command prompt shell for every command, passing the env vars to the underlying shell
• An important rework has been made to the way on how Zork++ can be invoked. Now only can use it from the project's root if no --root flag is set. With the flag remains unchanged
• Integration tests are now split by compiler and basic/partitions template, looking towards having different actions per every one on the future, so we can put a badge on our README.md allowing the visitors to know what compilers are completely up to date
• Preparing the deprecation of the system-headers build, waiting for GCC to finally support the build of the modularized standard libraries
• Minor upgrades to the cache direct hits performance

[gbm25]

In size.