Add win32 support for RelWithDebInfo builds

[shane-lawrence]

Motivation
As discussed in https://github.com/falcosecurity/falco/pull/3440/files#r1906703514, the method used to add separate debug symbols (objcopy) won't work on Windows. We should find an appropriate way to do this for Windows environments, but I don't think it should block the current PR.

Different sources have given me different instructions for how to do this with Visual Studio. Possibly with:

    set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "${CMAKE_CXX_FLAGS_RELWITHDEBINFO} /Zi")
    set(CMAKE_SHARED_LINKER_FLAGS_RELWITHDEBINFO "${CMAKE_SHARED_LINKER_FLAGS_RELWITHDEBINFO} /DEBUG")
    set(CMAKE_EXE_LINKER_FLAGS_RELWITHDEBINFO "${CMAKE_EXE_LINKER_FLAGS_RELWITHDEBINFO} /DEBUG")

Or this page suggests this:

elseif(...) # check for MSVC
    set_target_properties(
      ${PRJNAME}
      PROPERTIES
          DEBUG_SYMBOL_FILE "$<TARGET_PDB_FILE:${PRJNAME}>"
          DEBUG_SYMBOL_FILE_NAME "$<TARGET_PDB_FILE_NAME:${PRJNAME}>"
    )
    install(
        FILES
            "$<TARGET_GENEX_EVAL:${PRJNAME},$<TARGET_PROPERTY:${PRJNAME},DEBUG_SYMBOL_FILE>>"
        DESTINATION
            "${CMAKE_INSTALL_LIBDIR}"
    )

Some sources say that Visual Studio generates PDB files automatically with every build and we don't need to do anything. I don't have a test environment set up to work through this right now but I'm sure there's someone out there who does :).

For anyone using Windows but not Visual Studio, it's even less clear to me what the idiomatic way of doing this might be.

Feature

Alternatives

Additional context

[shane-lawrence]

Added a TODO comment for this here.

[FedeDP]

/milestone TBD

Since we are not shipping Windows artifacts, there is no hurry to fix this one.