This moves all the byte swapping utilities into a header named Swap.h.
A dedicated header is much more preferable here due to the size of the
code itself. In general usage throughout the codebase, CommonFuncs.h was
generally only included for these functions anyway. These being in their
own header avoids dumping the lesser used utilities into scope. As well
as providing a localized area for more utilities related to byte
swapping in the future (should they be needed). This also makes it nicer
to identify which files depend on the byte swapping utilities in
particular.
Since this is a completely new header, moving the code uncovered a few
indirect includes, as well as making some other inclusions unnecessary.
This fixes a minor bug where the IPL thinks the SRAM has been corrupted and forces you to re-set date/time and settings when you change language in Config -> GameCube while not skipping the IPL on boot.
Replaces them with forward declarations of used types, or removes them entirely if they aren't used at all. This also replaces certain Common headers with less inclusive ones (in terms of definitions they pull in).
