- Refactored the oembed plugin to use the Drupal core oembed logic, using media.oembed_iframe route. - oembed and embed field are two different templates for now, the oembed one uses the recomended progressive enhancement mode of plyr. The embed one uses the old version. - Experimental support for background video. The mode is enabled for both, but only tested on the oembed version. - Upgraded plyr to 3.7.2 - Splitted the plyr css/js into 2 seperate libraries. - Dropped PHP 7.3 support in composer.json, will drop Drupal 8 support in the next beta.