Simplify autoplay functionality.

Prevents all media in an entire carousel from simultaneously autoplaying in
some browsers. Changes the default autoplay value to true, and applies autoplay
configuration to all clips (whether from the gallery of most recent 'clip').

src/localize/languages/en.json

@@ -45,7 +45,7 @@
       "update_force": "Force card updates (ignore media playing / interaction)"
     },
     "event_viewer": {
-      "autoplay_clip": "Autoplay most recent clip (In 'clip' view)",
+      "autoplay_clip": "Autoplay clips",
       "draggable": "Event Viewer can be dragged/swiped",
       "lazy_load": "Event Viewer media is lazily loaded in carousel",
       "controls": {