Add description to monitor

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

db/patch-add-description-monitor.sql

@@ -0,0 +1,7 @@
+-- You should not modify if this have pushed to Github, unless it does serious wrong with the db.
+BEGIN TRANSACTION;
+
+ALTER TABLE monitor
+    ADD description TEXT default null;
+
+COMMIT;