Made the lamp work with ESPHome 2021.10.0

* Added OTA progress to the example.yaml.
* Updated the changelog for the ota progress support in the example.yaml.
* Implemented front_panel.set_level action for easier control of the slider LEDs.

* Document the newly found per-LED option of the front panel.
* Implement front panel HAL layer support.
* Implement actions for the output component to be able to control the LEDs.

* Updated documentation for 1.18.0 release with external components support.

* Moved example.yaml to the root dir, in line with the recommendations from the ESPHome external components guide.

* Normalized the version numbering for ESPHome references.

* Fixed the styling of the example.yaml references.

Co-authored-by: Maurice Makaay <mmakaay1@xs4all.net>