Tabs on dashboard.html now fade effect when switching between

First pass at HTML conversion from Master/Slave to Primary/Secondary (TODO: Backend)
Start work on migrating admin_auth_settings to Bootstrap v4
admin_setting_basic -> Change plain text for On/Off to toggles in current state, and changed "Action" column to the opposite toggle of current setting
dashboard_domain -> Reduce deuplicate code for the new dropdown-menu for Actions
register -> Add exclamation icon in front of error text
template_add -> changed box-body to card-body
user_profile -> Fixed tab naviation for Bootstrap v4. Tabs also fade between changes

powerdnsadmin/templates/admin_setting_pdns.html

@@ -34,7 +34,7 @@
     <div class="container-fluid">
       <div class="row">
         <div class="col-4">
-          <div class="card shadow">
+          <div class="card shadow card-outline card-secondary">
             <div class="card-header">
               <h3 class="card-title">PDNS Settings</h3>
             </div>
@@ -75,7 +75,7 @@
           </div>
         </div>
         <div class="col-8">
-          <div class="card shadow">
+          <div class="card shadow card-outline card-secondary">
             <div class="card-header">
               <h3 class="card-title">Help</h3>
             </div>
@@ -88,7 +88,7 @@
                 <dt>PowerDNS API Key</dt>
                 <dd>Your PowerDNS API key.</dd>
                 <dt>PowerDNS Version</dt>
-                <dd>Your PowerDNS version number (eg. 4.1.1).</dd>
+                <dd>Your PowerDNS version number (eg. 4.7.0).</dd>
               </dl>
               <p>Find more details at
                 <a href="https://doc.powerdns.com/md/httpapi/README/">https://doc.powerdns.com/md/httpapi/README/</a>