added keybrightness_F5.json, a single-key keyboard brightness controller
added keybrightness_F5.json, a single-key keyboard brightness controller

pqrs-org/KE-complex_modifications,pqrs-org/KE-complex_modifications,pqrs-org/KE-complex_modifications,pqrs-org/KE-complex_modifications,pqrs-org/KE-complex_modifications,pqrs-org/KE-complex_modifications