Unit tests for gameboy instructions

[marcluque]

I propose to start implementing unit tests for instructions. This should be paired with an action that runs the tests for PRs.

TODO list for this issue:

• Add Criterion as test suite to CMake workflow (#13)
• Add Github action to run tests with Criterion + CMake for PRs (#17 & #19)
• Implement unit tests for all gameboy instructions (see below for PRs)

The following list shows a check list for the unit test implementation progress of the 512 gameboy instructions:

Inst	Unit Tests	#PR
LD m,n	✅	#32/#36
LD mm,n	✅	#44
ADD A,n	✅	#7/#34
ADC A,n	✅	#15
SUB A,n	✅	#22
SBC A,n	✅	#30
AND A,n	✅	#42
OR A,n	✅	#46
XOR A,n	✅	#49
CP A,n	✅	#53