Support audio streams

1. +++ b/media_entity_audio.module
   @@ -31,17 +37,41 @@ function media_entity_audio_preprocess_media_audio_file_formatter(&$vars) {
   +  $vars['sources'] = array_map(function ($item) {
   +    return [
   +      'url' => $item,
   +      'type' => _media_entity_audio_map_mime(\Drupal::service('file.mime_type.guesser')->guess($item)),
   +    ];
   +  }, $vars['sources']);
   

   this is a bit hard to read, unclear what $item is, maybe store $guesser in a variable so the line is a bit shorter and easier to read? inside or outside, could also be outside with a use ($mime_type_guesser).

2. +++ b/media_entity_audio.module
   @@ -31,17 +37,41 @@ function media_entity_audio_preprocess_media_audio_file_formatter(&$vars) {
   +function _media_entity_audio_map_mime($mime) {
   

   not a big fan of _underscore functions, but this is just extracted out to avoid duplication, so fine I guess

3. +++ b/src/Plugin/Field/FieldFormatter/AudioStreamHTML5.php
   @@ -0,0 +1,88 @@
   + * @FieldFormatter(
   + *   id = "audio_stream_html5",
   + *   label = @Translation("Audio Stream (HTML5)"),
   + *   field_types = {
   + *     "link"
   

   in jw_player I used the same formatter for both, but quite possibly easier to separate here.

   Especially since something like this might actually land in core as part of #2831944: Implement media source plugin for remote video via oEmbed (did not check if that's just video or also audio), so might not even be needed for 8.x-2.x?

Ah the core issue seems to focus on oembed support, which then wouldn't cover this. That said, core (8.5.x I think) got audio and video html5 formatters recently, so that *could* possibly be also extended there.

#2927166: Allow HTML5 video/audio formatters for link fields on Media entities to discuss adding that to core.

That will only get into 8.5.x I think, so unless we want to wait that long (and it won't be possible to use that patch in 8.4.x), we probably still need those formatters here, at least temporary?

This is the first iteration of a patch that only keeps support for streams, as a new audio_stream source plugin. Includes an update function that converts the existing ones either to audio_file (core) or audio_stream, including updating the view display config for audio_file.

The update function does not automatically uninstall itself, but sites may chose to do so if they only used audio files.

This will become a new 8.x-3.x branch.

A binary patch for the removed fallback thumbnail (core has a audio.png too)

Using the correct test base class now.

Forgot --binary again.

And fixing the test.