Bring GPU support to CMake and improve how Make handles the ROCm library build

[aristocratos]

@imwints Great! Let me know when ready to merge.

[imwints]

If CI passes this is done. To sum up:

• CMake can build with GPU support
• CMake can statically link to ROCm
• Improved the build of ROCm from Make
  • Only build the static library
  • Build an optimized library
  • Respect DEBUG=true
  • Build with LTO
  • Add clean/distclean for ROCm

[imwints]

@aristocratos Also tried the 5.7.x branch of ROCm which at least compiles... I have no way of testing the runtime behavior.