embed improvements:

- show back, forward options in default embed mode
- add extra options menu in embed mode, including 'purge cache + full reload'
- responsive replay bar buttons: show in menu when tablet or mobile, in non-embed mode, only show on mobile
- 'full' embed mode, show only logo and info menu, no user guide/terms

src/embed.js

@@ -105,7 +105,7 @@ class Embed extends LitElement
         changedProperties.has("source")) {
 
       if (this.embed === null) {
-        this.embed = this.url ? "replayonly" : "";
+        this.embed = this.url ? "replay" : "full";
       }
 
       this.paramString = new URLSearchParams({