Create SGAction class

Create a basic class for SGAction

Core features:

• enable / disable state, optionally driven by a <condition>
• trigger and release bindings
• translated label and description
• binary (toggle) mode distinct label + description based on state
  • value property and/or condition
  • pass value to bindings as an argument
• repeating (periodic) actions with a specified interval
• parse from property description
• alternate mode trigger and release, with corresponding label / description

Bonus features:

• enumerated mode, with per index label+description
  • requires a value property / expression
  • similar to toggle, pass value to bindings