Custom Sensors

New Feature

What does this MR do?

This MR adds a new Custom Sensor Repo and UI controls. Currently it allows one to create their own sensor based on a mix of other sensors. This also deprecates the Composite Repo, which is not hidden in the UI and will be removed in a future release.

Related issues

completes #211 (closed)

Checklist

• Application works as expected when running from source
• There are dependency changes
• Liquidctl device mock tests are successful (if applicable)
• Any needed documentation changes have been made
• This MR is ready to be merged