Complete carousel refactor.

Reduces one layer of DOM nesting for simplication, uses the latest Embla
version, unittests for everything.

src/utils/media-info.ts

@@ -112,7 +112,7 @@ export function isValidMediaLoadedInfo(info: MediaLoadedInfo): boolean {
   );
 }
 
-// Facilities correct Typescript typing of media:loaded event handlers.
+// Facilitates correct Typescript typing of media:loaded/unloaded event handlers.
 export interface FrigateMediaLoadedEventTarget extends EventTarget {
   addEventListener(
     event: 'frigate-card:media:loaded',
@@ -122,6 +122,11 @@ export interface FrigateMediaLoadedEventTarget extends EventTarget {
     ) => void,
     options?: AddEventListenerOptions | boolean,
   ): void;
+  addEventListener(
+    event: 'frigate-card:media:unloaded',
+    listener: (this: FrigateMediaLoadedEventTarget, ev: CustomEvent) => void,
+    options?: AddEventListenerOptions | boolean,
+  ): void;
   addEventListener(
     type: string,
     callback: EventListenerOrEventListenerObject,
@@ -135,6 +140,11 @@ export interface FrigateMediaLoadedEventTarget extends EventTarget {
     ) => void,
     options?: boolean | EventListenerOptions,
   ): void;
+  removeEventListener(
+    event: 'frigate-card:media:unloaded',
+    listener: (this: FrigateMediaLoadedEventTarget, ev: CustomEvent) => void,
+    options?: boolean | EventListenerOptions,
+  ): void;
   removeEventListener(
     type: string,
     callback: EventListenerOrEventListenerObject,