* 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>
Maurice Makaay