Optional PDB files in release mode for MSVC

[alxvth]

We would like to use PDB files for error handling with sentry in Release mode builds on Windows.

The main differences between RelWithDebugInfo and Release is the addition of the compile option /Zi and the link option /DEBUG which are responsible for generating full PDB files. Here, we additionally add /Zf which enables faster PDB generation in parallel builds, which we ensure with /MP. The option MV_RELWITHDEBUGINFO indicates whether PDB files should be generated for Release builds. This option is OFF by default, except on the CI.

This PR refactors the setup of global CMake variables for OS-dependent compiler settings a bit. It introduces the cmake/mv_project_defaults.cmake helper file which can be re-used by plugins in order to not repeat the same setup in all projects.

Additionally:

• set CMAKE_MSVC_RUNTIME_LIBRARY instead of adding the multi-threaded runtime option multiple times
• add /Zc:preprocessor to the CMAKE_CXX_FLAGS
• remove /permissive- which is implicitly set by the /std:c++20 option

Drive-by:

• Simplify some target property calls
• Fix setting CMake options from conanfile.py: we should use cache_variables instead of variables

Open questions:

• Which PDB files do we want to keep in CI builds? Both for RelWithDebInfo and Release builds or just for the latter?

Once this is merged, we should update all relevant plugins to use mv_project_defaults() after their find_package(ManiVault ...) calls and remove the then obsolete CMake options sections.

Closes #1187. See there for a some additional info.