Add volume management to AVR

templates/index.html

@@ -83,7 +83,6 @@
     </div>
   </div>
 
-  {% if not avr %}
   <div class="volume">
     <button class="control-btn step" data-delta="-1" aria-label="{{ room.label }}: volume down">
       <svg viewBox="0 0 448 512" aria-hidden="true"><path d="M432 256c0 17.7-14.3 32-32 32L48 288c-17.7 0-32-14.3-32-32s14.3-32 32-32l352 0c17.7 0 32 14.3 32 32z"/></svg>
@@ -93,7 +92,6 @@
       <svg viewBox="0 0 448 512" aria-hidden="true"><path d="M256 80c0-17.7-14.3-32-32-32s-32 14.3-32 32l0 144L48 224c-17.7 0-32 14.3-32 32s14.3 32 32 32l144 0 0 144c0 17.7 14.3 32 32 32s32-14.3 32-32l0-144 144 0c17.7 0 32-14.3 32-32s-14.3-32-32-32l-144 0 0-144z"/></svg>
     </button>
   </div>
-  {% endif %}
 
   <div class="actions" data-role="actions" hidden>
     {% if not avr %}