* initial DOCS.md for Addon * links to Mosquitto and Adguard * replaced _ by . for PV-Strings * mentioned add-on installation method in README.md * fix most of the markdown linter warnings * add missing alt texts * added nice add repository to my Home Assistant badges --------- Co-authored-by: Michael Metz <michael.metz@siemens.com> Co-authored-by: Stefan Allius <stefan.allius@t-online.de>