outputconfigurationstore: implement better screen mirroring
Instead of KScreen trying to move and scale outputs in a way that kind of looks like mirroring, this makes KWin aware of which outputs replicate which, and makes it responsible for implementing mirroring in whatever way is best.
This commit implements simliar workarounds like KScreen had, with the only real difference being that it avoids modifying the source display mode and position. A better implementation can replace that bit later on, while making use of the same information stored in the configuration.
Depends on !7465 (merged) and libraries/plasma-wayland-protocols!102 (merged)
Edited by Xaver Hugl