1: reduce python whl package size
2: unify api link logic on all OS
3: add option: MGE_WINDOWS_BUILD_WITH_STATIC_CRT
    --- default OFF
    --- if build CRT(vc runtime) with STATIC with megengine.dll
        some CRT api will crash, for example, flush, so if you
        build with static megengine, and do not want to install CRT
        you can set MGE_WINDOWS_BUILD_WITH_STATIC_CRT TRUE
    --- how to install CRT:
        https://docs.microsoft.com/en-us/cpp/windows/latest-supported-vc-redist?view=msvc-160
        install VC_redist.x64.exe
4: rename megengine_export to megengine_shared(only export needed symbols ),
   caused by runtime symbols conflict with pytorch

GitOrigin-RevId: 93d8d80f29

exception namespace when disable rtti

GitOrigin-RevId: c42f5adffd

GitOrigin-RevId: 04f39943c4