Proper (extensible) testing

[mrexodia]

Currently the "tests" are just running the "getting-started" examples. This doesn't scale and makes it difficult to find regressions.

The test framework:

• A single unified Visual Studio solution with test executables
• Build the solution with GitHub Actions so new feature PRs can be tested in the same PR
• A dump of a minimal Windows usermode environment (ntdll, kernel32, kernelbase, x64+x86)
• A dump of a more "complete" environment (winsock, cryptapi, advapi32, shell32, user32, etc.)
• Load the test executables with dp.map_module
• Execute the (exported) test functions on a fresh Dumpulator instance each time
• Calculate code coverage per test

Necessary tests:

All of these should use /NODEFAULTLIB to not have to care about the MSVC runtime initialization (which uses a lot of unimplemented syscalls)

• ExceptionTest (for testing different exception scenarios)
• LoadLibrary (to test map_module and the whole PEB loading chain)
• StringEncryptionFun
• More depending on coverage...