Turbo migration to GpioMappings needs to also migrate into profiles

[bsstephan]

Beta tester report against pre-0.7.8.

Expected Behavior

• Turbo pin is assigned to the turbo GPIO action on all four profiles

Current Behavior

• Turbo pin is only assigned to turbo in Profile 1, Profiles 2-4 still show it assigned to addon

I also think we should remove the comment // Check for additional migrations for features 0.7.6+ and rename checkAdditionalMigrations as it gives the impression that all future migrations will go in that method, which I don't think is necessarily a good idea as future migrations may be complicated and/or non-repeatable, and eventually this method will get obnoxious to run at every boot. I would make it like the other migrations.