Podcast plugin needs an update

[onli]

While the RSS part of the plugin seems to work, the bundled players are very outdated. The plugin would profit from fixes for the PHP 8 notices, and a new JS based player instead of the current selection. Maybe similar to how https://github.com/onli/simplepodcast tried an alternative approach?

[onli]

@garvinhicking I will ping you here since you were involved with the original plugin, just in case.