Disable tab if its settings are not on the whitelist

Closes #113 (closed)

src/views/settings/components/ActivityPub.vue

@@ -3,7 +3,7 @@
     <el-form ref="activitypubData" :model="activitypubData" :label-position="labelPosition" :label-width="labelWidth" data-search=":activitypub">
       <setting :setting-group="activitypub" :data="activitypubData"/>
     </el-form>
-    <el-divider class="divider thick-line"/>
+    <el-divider v-if="activitypub" class="divider thick-line"/>
     <el-form ref="userData" :model="userData" :label-position="labelPosition" :label-width="labelWidth" data-search=":user">
       <setting :setting-group="user" :data="userData"/>
     </el-form>