Git conversion: Make reactos the root directory, move rosapps, rostests, wallpapers into modules, and delete rossubsys.
[WIN32U] Rename win32kdll to win32u, which is the "official" name on Windows 10 svn path=/trunk/; revision=76026
[ROSTESTS] Use the new header with SPDX license identifier for my printing-related API tests svn path=/trunk/; revision=75992
[ROSAUTOTEST] Use the new header with SPDX license identifier and remove dead source files. svn path=/trunk/; revision=75991