chore: move .gitignore to root

chore(src): move source to source/ folder

feat(src): add clock application and initialization

feat(src): add brightness manager

feat(src): add module for linear interpolation

feat(src): add basic button representation

feat(src): add app state with calendar

feat(src): add CountDown abstraction

feat(src): add clock seven segment display support

chore(src): add essential project files