profile: drop gravatar support

gravatar is owned by an external entity (Automattic) and we have an
unnecessary dep to this service. users can just upload a profile pic

dashboard/src/views/ProfileView.vue

@@ -270,7 +270,7 @@ onMounted(async () => {
 
       <div style="display: flex; flex-wrap: wrap; gap: 20px">
         <div style="width: 128px;">
-          <ImagePicker :src="user.avatarUrl" fallback-src="/img/background-image-placeholder.svg" :size="512" :save-handler="onAvatarSubmit" display-width="128px"/>
+          <ImagePicker :src="user.avatarUrl" fallback-src="/img/avatar-default-symbolic.svg" :size="512" :save-handler="onAvatarSubmit" display-width="128px"/>
         </div>
         <div style="flex-grow: 1;">
           <SettingsItem>