JS frontend stuff

Move old ember frontend to properly named folder
Add vue based new frontend

frontend-old-ember/app/components/util/mail-entry.hbs

@@ -0,0 +1,18 @@
+<div class="mail-entry {{@wrapper-classes}}">
+  <label>
+    Email
+    {{!--<div class="filling-spacer"/>--}}
+    <Input
+      class="mail-input {{if this.mailOk "mail-input-ok" "mail-input-error"}} {{@input-classes}}"
+      @type="text"
+      @value={{this.args.data.mail}}
+      placeholder="Email address"
+      {{on "change" this.checkMail}}
+    />
+  </label>
+  {{#if this.mailOk}}
+    <p class="mail-ok mail-status">&#10004;</p>
+  {{else}}
+    <p class="mail-error mail-status">X</p>
+  {{/if}}
+</div>