Debugger: Implement little endian memory view support

[F0bes]

Description of Changes

Support little and big endian view modes within the debuggers memory view via context menu action.

Rationale behind Changes

Big endian values, although easier to work with in this context, don't make sense for the PS2.

Suggested Testing Steps

Please test all byte grouping modes. Copying memory, pasting memory, using keyboard arrows to move around with both big and little endian modes.

fixes #7998