[doc] CMakeLists.txt: Install documentation.

The previous commit included some of this, including adding the
doc subdirectory and installing the README.
[data] Added Border.png and Codes.xml from the latest 3.0 release.

Install the data in mods/.

SADXModLoader: Install the DLL and PDB in mods/.

doc/CMakeLists.txt: Minor comment change.
[extlib] Install BASS and associated DLLs.

CMakeLists.txt: Rearranged ADD_SUBDIRECTORY() calls to match mcrecover.