Removed some dangling notes

Schematics refactoring: - New sheet reserved to video memory. - Removed video memory parts inside video_generation. - Removed video memory parts inside GPIO. - Generic cleanup to keep all circuits inside each sheet.

parallel port, which is absolutely not a centronics port

Serial communication interface

IO addressing space multiplexing and small IO description

Reset circuit

Upgraded to kicad 7

Add daughterboard schematics.

Specialize generic IO sheet to SIO (serial) related.