Reference #13250

Apply minimum `C` in `M303`. `PID_autotune()` needs to be called with a 'C'ycles-parameter >2 to give meaningful (different from 0) PID-factors. Therefore silently raise C to 3. Fixing one aspect of #13104

* Make ExtUI respect MAXTEMP limits
  - Temperatures are now clamped by MAXTEMP limits rather than arbitrary values.
* Speed up USB init, add status
  - Speed up USB initialization
  - Show status message if init failed
* Enable status messages for EXTENSIBLE_UI
* Adjust max limit to MAX_TEMP - 15
* Misc. tweaks to formatting, const, etc.

* Optimize target_extruder, ignore T with mixing
* Give G-code Tn parity with tool_change

* 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.

Co-Authored-By: Giuliano Zaro <gmagician@users.noreply.github.com>

Fix compile error intruduced with M109 modification

Fix #10699

Use macros that explicitly avoid double-evaluation and can be used for any datatype, replacing `min`, `max`, `abs`, `fabs`, `labs`, and `FABS`.

Co-Authored-By: ejtagle <ejtagle@hotmail.com>

* Remove obsolete strings
* Tweak some static consts
* Reset LCD status to fallbacks

* 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

- `M666` is static, not inline
- Disambiguate some stepper macros

Fix #10012

Based on #7883 by @studiodyne

Same as #7728 but for 2.0.x,
Lot of cleanup and remove references in whole code to other "LED files" than leds.h. Now will be much easier to add next drivers/libraries. e.g. FastLED. But bad news, currently FastLED is suporting only RGB devices (no RGBW)

Addressing #7707