Move setting of Save context flags from Patches to Savecontext

[GSKirox]

Another PR with the goal of cleaning Patches.py a tiny bit.
Instructions that write initial save context flags have been regrouped and divided in two functions moved in SaveContext.py :

• write_qol_save_context_flags, which are currently always on whatever the settings chosen. Since they don't use any other data, this can be a member of SaveContext.
• write_settings_dependent_save_context_flags for the rest, in a function separate of the class.

I chose to let a couple of these flags in Patches.py if they were part of a bigger code block for their specific settings, since i felt it would make it less readable if that flag was set somewhere else.

This should be strictly indentical in behaviour, barring of course any mistake.

[fenhl]

Generated some sample seeds to compare to current Dev (with seed salting disabled to allow direct comparisons) and while the generated roms are not literally identical due to the order of items in SaveContext.save_bits and SaveContext.save_bytes changing, they still seem to be functionally identical.