* Validate preset names and group names at compile time (fixes #15)

* Small fix for using a less confusing var name.

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

* Implemented compatibility with color mode support in the latest Home Assistant + ESPHome.

* Made the code compile with both v1.20.* and v.1.21.0.

* Made the code compile with both v1.20.* and v.1.21.0.

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

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

* 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.

Compatiblity fix for new coroutine setup in ESPHome.

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

Thanks Jos!

* 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>

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

As I found out by just trying it out, the debug pad for GPIO2 can be used for I/O purposes. I managed to hook up a microwave presence sensor to the debug pad, with great success. The documentation is updated with that new knowledge.

Explained the need for a custom platform package for arduino-esp32 in the technical information.