Add popularLabels computed property.

Returns a list of labels used in the current view,
in order of popularity (most used first).

NOTE: this property is not actually used. It's
technically dead code.

lib/www/client/source/src/views/Log.vue

@@ -287,6 +287,18 @@ export default {
         }
       }
       return filtered;
+
+    },
+
+    popularLabels () {
+      const tuples = this.items.flatMap( i => i.labels )
+      .filter( l => (this.labels[l]??{})?.model?.user )
+      .reduce( (acc, cur) => {
+        return cur in acc ? ++acc[cur][1] : acc[cur]=[cur,1], acc
+      }, {});
+
+      return Object.values(tuples)
+      .sort( (a, b) => b[1]-a[1] );
     },
 
     defaultSequence () {