ai-embed: removed legacy code and fixed supported embed providers

wp-content/plugins/ai-embed/ai-embed.php

wp-content/plugins/ai-embed/embed-function.php

wp-content/plugins/ai-embed/flowplayer/LICENSE.md

wp-content/plugins/ai-embed/flowplayer/flowplayer-3.2.5.swf

wp-content/plugins/ai-embed/flowplayer/flowplayer-5.3.2.zip

...nt/plugins/ai-embed/flowplayer/flowplayer.audio-3.2.1.swf

...plugins/ai-embed/flowplayer/flowplayer.controls-3.2.3.swf

wp-content/plugins/ai-embed/flowplayer/flowplayer.js

wp-content/plugins/ai-embed/flowplayer/flowplayer.min.js

.../ai-embed/flowplayer/flowplayer.pseudostreaming-3.2.5.swf

wp-content/plugins/ai-embed/flowplayer/flowplayer.swf

wp-content/plugins/ai-embed/flowplayer/index.html

...nt/plugins/ai-embed/flowplayer/js/flowplayer-3.2.4.min.js

wp-content/plugins/ai-embed/flowplayer/js/index.html

wp-content/plugins/ai-embed/flowplayer/js/style.css

wp-content/plugins/ai-embed/flowplayer/skin/all-skins.css

wp-content/plugins/ai-embed/flowplayer/skin/functional.css

wp-content/plugins/ai-embed/flowplayer/skin/img/black.png

wp-content/plugins/ai-embed/flowplayer/skin/img/black@x2.png

...ntent/plugins/ai-embed/flowplayer/skin/img/play_black.png