Add note assignment

[cracked-machine]

After selecting step position:

• there should be a short timeout while user is able to select the note assignment via the rotary encoder.

• user can manually press the encoder switch to confirm the note assignment and cancel the timeout

User can select another step position before timeout, which will cancel the timeout on the previous selection, assign the previously used note on the new selection and start a new timeout on the new selection.

[cracked-machine]

https://github.com/cracked-machine/StepSequencer_SW/commit/9ee0b8ddd4ddca1af81a129dfd38cd054160363c

[cracked-machine]

Two modes are currently implememented:

• tempo_adjust
• note_assign

but currently there is no way for the user to switch between the two.

There are two options:

1. Automatically switch from note_assign mode to tempo_adjust mode when user selects a step. Then use a one-shot timer to return to tempo_adjust mode after a short timeout.
2. Make the tempo_adjust and note_assign modes user-selectable via a tactile button.

[cracked-machine]

enabled mode selection via rotary encoder switch

https://github.com/cracked-machine/StepSequencer_SW/commit/7cb770d1b3c80fcd4d21fe51540154b6cdf90cbe