Add description to monitor

* Add description to monitor model
* Add description field to database
* Add english and spanish translation for description
* Closes: #482

src/pages/Details.vue

@@ -2,6 +2,7 @@
     <transition name="slide-fade" appear>
         <div v-if="monitor">
             <h1> {{ monitor.name }}</h1>
+            <p>{{ monitor.description }}</p>
             <div class="tags">
                 <Tag v-for="tag in monitor.tags" :key="tag.id" :item="tag" :size="'sm'" />
             </div>