Add pop-out player for audio/video in web UI (#14870)

app/javascript/mastodon/actions/picture_in_picture.js

app/javascript/mastodon/components/animated_number.js

app/javascript/mastodon/components/icon_button.js

...ipt/mastodon/components/picture_in_picture_placeholder.js

app/javascript/mastodon/components/status.js

app/javascript/mastodon/components/status_action_bar.js

app/javascript/mastodon/containers/status_container.js

app/javascript/mastodon/features/audio/index.js

...mastodon/features/picture_in_picture/components/footer.js

...mastodon/features/picture_in_picture/components/header.js

app/javascript/mastodon/features/picture_in_picture/index.js

...pt/mastodon/features/status/components/detailed_status.js

app/javascript/mastodon/features/status/index.js

...javascript/mastodon/features/ui/components/media_modal.js

...javascript/mastodon/features/ui/components/video_modal.js

app/javascript/mastodon/features/ui/index.js

app/javascript/mastodon/features/video/index.js

app/javascript/mastodon/reducers/index.js

app/javascript/mastodon/reducers/picture_in_picture.js

app/javascript/styles/mastodon/components.scss