refactor: extract action buttons

[DSIW]

• Extract action buttons
• Move to components

Feature summary

QA checklist

• Read state (state & power state)
• Read primary battery SOC
• Read primary battery cycles
• Read secondary battery SOC
• Read secondary battery cycles
• Read seat closed
• Read handlebar
• Read AUX SOC
• Read CBB SOC
• Read CBB charging state
• Update ping
• SOCs are cached (after app restart)
• Commands can be sent (locking & hibernation)

[DSIW]

That needs to be fixed in a separate PR related to the issue

[TheFreal]

1. This feels like really poor style, as it turns what was previously one reusable widget into a whole folder of single-purpose files.
2. The action buttons will probably change significantly in Home Screen and controls section need a UX rework #43 (which this structure would make way harder)
3. I'm not yet convinced of the flutter-on-wear approach in its entirety
   For those reasons, I'm not merging for now :/