* Encapsulate common LCD code in a singleton
* Depend more UBL code on UBL_DEVEL_DEBUGGING
- Since most users don't need the debugging on at all times, this helps reduce the default build size for UBL by over 2K, a little closer to fitting on 128K boards.
* Automatically reset stepper timeout in manage_inactivity
Any code that adds moves to the planner can skip resetting the stepper timeout. We can let `idle` / `manage_inactivity` reset the timer whenever it detects any moves in the planner.
* blocks_queued => has_blocks_queued
