CMake: use ARPA2CM 1.0 and install cmake parts in the right place
- use ARPA2CM 1.0. There's no functional reason for this (except see below), but makes Quick DER consistent with earlier parts of the stack and includes cohesiveness of the products.
- has been installing CMake files to Steamworks/ rather than Quick-DER/ for over six months,
- use clearly-named helper variable from ARPA2CM 1.0 instead.
This is an MR because Rick needs to fiddle with mkhere bits as well to make CI work.