Create `matrix.h` and `matrix_stack.h`

[Dragorn421]

Create matrix_stack.h with all the stack-based matrix manipulation functions, and matrix.h with the rest of the matrix functions (besides the gu ones which should be in libultra's gu.h (and currently are in functions.h))

[mzxrules]

PR #1972 also conflicts with this because I implemented my own sys_matrix.h that mimics MM's own sys_matrix.h

I'm fine with dropping the inclusion of sys_matrix.h in #1972 in favor of this pr, though I would prefer the two headers stay mostly consistent between games.

[Dragorn421]

I don't know where to take this