[rlgl] Clean up Matrix handling and label implicit transposes in rlgl.h

[noinodev]

raylib convention uses m0..m15 named fields for Matrix operations:

• Use named fields in rlTranslatef, rlScalef and rlMatrixIdentity instead of array literals

Additionally, the memory order of struct Matrix is row-major, therefore some functions implicitly convert to column-major and vice-versa:

• Label implicit row-major to column-major transpose in MatrixToFloatV
• Label implicit column-major to row-major transpose in rlMultMatrixf
• Update rlSetUniformMatrix to use rlMatrixToFloat convention

Aimed for readability and maintainability, does not change behaviour.

[raysan5]

@noinodev thanks for the review!