atmosphere: extract API version management to common folder

Add and fix copyright notices for better GPL compliance (thanks @naehrwert and @CTCaer).

Boot: Fully implemented GPIO and PINMUX handling

Boot: Implement PMC wake pin events

Boot: Implement pinmux drive pad configuration

boot: build as KIP (thanks @fincs !)

Fix the syntax errors in the boot JSON files

Fix latest commit not building

Boot: Implement pinmux setup

boot: Use fsdevMountSdmc & fsdevUnmountAll

Boot: Fleshing out more low level stuff ...

Add register read/write for 2.0.0+ (with svcReadWriteRegister)
Add hardware type recognition
Implement PMC clock out configuration
Implement PINMUX park updating

boot: Make gpio helper functions internally linked

boot: Fix missing argument for gpio_base_vaddr

boot: Fix invalid usage of svcQueryIoMapping

Replace std::make_tuple with simpler syntax (#77) ...

* boot2: Simplify g_additional_launch_programs

It appears that Stratosphère is targeting C++17. In C++17,
std::make_tuple is not required for initialisating a tuple anymore.
Same thing, but less typing

* Replace std::make_tuple with {}

More readable and less noise. Also fixes two missing return statements.

Boot: Implement initial GPIO configuration

Boot: Fix JSON mappings to be RW (instead of RO)

Boot: Initial skeleton and 1.0.0 GPIO voltage switch.