Chore: convert "unnamed" into constant

- "Unnamed/Unknown" simplified into just "Unnamed"
- Phrase variations have their own constants

src/views/DIDView.vue

@@ -290,6 +290,7 @@ import {
   NOTIFY_SERVER_ACCESS_ERROR,
   NOTIFY_NO_IDENTITY_ERROR,
 } from "@/constants/notifications";
+import { UNNAMED_PERSON } from "@/constants/entities";
 
 /**
  * DIDView Component
@@ -549,7 +550,7 @@ export default class DIDView extends Vue {
         contact.registered = true;
         await this.$updateContact(contact.did, { registered: true });
 
-        const name = contact.name || "That unnamed person";
+        const name = contact.name || UNNAMED_PERSON;
         this.notify.success(
           `${name} ${NOTIFY_REGISTRATION_SUCCESS.message}`,
           TIMEOUTS.LONG,