Draft prerelease 3.4.57

@farhi includes mcdoc that writes to DEST_DATADIR_DOC (see Locations.cmake)

I "hardcode" to share/doc/${FLAVOR} instead of using CMAKE_INSTALL_DOCDIR which will append project info from individual CMakeList files.

Tested using buildscripts/ approach on Linux, will follow up with tests on conda, macOS, Windows "monolithic" later