user joined notification template

src/metabase/email/user_joined_notification.mustache

+{{> metabase/email/_header }}
+  <div style="padding: 2em 4em; border: 1px solid #dddddd; border-radius: 2px; background-color: white; box-shadow: 0 1px 2px rgba(0, 0, 0, .08); text-align: center;">
+    <div style="padding-bottom: 1em;">
+      <h2 style="font-weight: normal; color: #4C545B;line-height: 1.65rem;">
+        {{joinedUserName}}
+        {{#jonedViaSSO}}created a Metabase account.{{/joinedViaSSO}}
+        {{^joinedViaSSO}}accepted your Metabase invitation.{{/joinedViaSSO}}
+      </h2>
+      <h4 style="font-weight: normal;">
+        <a style="color: #4A90E2; text-decoration: none;" href="mailto:{{invitorEmail}}">
+          {{joinedUserEmail}}
+        </a>
+        joined {{#sso}}via Google Auth{{/sso}} at {{joinedDate}}
+      </h4>
+    </div>
+    <div style="padding: 1em;">
+      <a style="display: inline-block; box-sizing: border-box; text-decoration: none; font-size: 1.063rem; padding: 0.5rem 1.375rem; background: #FBFCFD; border: 1px solid #ddd; color: #444; cursor: pointer; text-decoration: none; font-weight: bold; border-radius: 4px; background-color: #4990E2; border-color: #4990E2; color: #fff;" href="{{joinedUserEditUrl}}">
+        Edit {{joinUserName}}'s settings
+      </a>
+    </div>
+    <div style="padding-bottom: 2em; font-size: x-small;">
+      Button not working? Paste this link into your browser:<br/>
+      {{joinUrl}}
+    </div>
+  </div>
+{{> metabase/email/_footer }}