Refactor equipment maintenance components

[axelboc]

This refers to the SampleChangerMaintenance, HarvesterMaintenance and PlateManipulatorMaintenance components rendered on the Equipment page.

• Move ActionGroup, ActionButton, ActionField into separate files and refactor them slightly (notably, ActionButton no longer takes care of sending the maintenance command; it just exposes an onClick prop).
• Let PlateManipulatorMaintenance use those "Action" components (it was using its own duplicated "Action" components).
• Refactor the "Maintenance" components to function components, refactor them to remove unnecessary render methods (renderActionGroup, renderActionButton, etc.)
• Let the "Maintenance" retrieve the state they need from the Redux store instead of passing it down from EquipmentContainer.

[marcus-oscarsson]

Ahh, it always feels nice with a good cleanup :) Thanks !