fusee_cpp: validate mtc overlay before jumping to it. ...

mtc will jump back to us, so we need a compatible binary.

This also makes some changes to our layout to minimize the likelihood of
an incompatible mtc binary (I made some arbitrary .text/.rodata/.rwdata changes)
and saw identical mtc binaries, so hopefully this all works out.

fusee_cpp: implement nogc patches

fusee_cpp: implement cpu startup

fusee_cpp: implement exosphere load/configuration

fusee_cpp: add logic for loading mtc overlays