* remove spare dependencies from composer.json
* add important javascript files in templates directoy and register in mixin.config
* refactor rvktree.js
** call only on RVK site by template directly
** add fallback for translationShow variable
* add default url and default rvk sections in Rvk.php
* add Readme

* TODO:
** rename master to main
** add css, icons for plus and minus
** caching
** copy repo to packagist