Template and styles for inline oembed videos

[alisonjo315]

We're switching from video_embed_field to Drupal core "oembed" functionality for YouTube videos:
https://github.com/CU-CommunityApps/cd_drupal_upstream/issues/42

• Work in progress on "video" multidev of the upstream demo site.
• Demo page with inline oembed video, for testing this cwd_base work:
  • https://video-cddemo.pantheonsite.io/test-page-inline-video
  • (i.e. you can see field--field-media-oembed-video.html.twig is already in use on that multidev)

Accompanying tasks for our Drupal base theme -- can happen any time (no need to wait for the cd_drupal_upstream issue to be complete):

• Remove extra "div" wrapper from video embed field output:
  • Create field--field-media-oembed-video.html.twig -- simply to use _field--less-wrapped.html.twig (same as field--image.html.twig).
• Configure view modes (on CLASSE and VPUE and CVM, we provided "default" and "medium sized") -- THEN, check text formats and make sure "video"/"remote video" is enabled, and the "default" and "medium" view modes are available.
  • In theory, can skip this on CD Demo, and just do it on sites that use this functionality -- they can copy the view mode and CKEditor settings CLASSE/VPUE.
  • Don't forget to make sure Media Library "advanced UI" is enabled: /admin/config/media/media-library
• Add style rule to Drupal stylesheet, for inline video embeds:
  • Reference: https://www.drupal.org/project/drupal/issues/3060968#comment-14968763

iframe.media-oembed-content {
  display: block;
  width: 100%; 
  height: auto;
  aspect-ratio: 16 / 9;
}

---

FWIW: This work is already happening on VPUE (as of 2023-09-13, the oembed field template is done, the style rule will be done soon).

[alisonjo315]

Aspect ratio issue on d.o is still open, but when I put videos on the under-development CLASSE site, they seem okay?? -- bottom of this demo page:
https://dev-classe.pantheonsite.io/about

[alisonjo315]

Part 1 (new field template) is done and merged (#77). Per my comment in December, it's possible that part 2 is not necessary, I'm really not sure 🤷‍♀️

Edit: Then I added "part 3" this evening -- but maybe that doesn't need to happen on CD Demo itself........