chore: migrate mail themes to shared framework and locked upstream inputs

framework/mail/base/action.tmpl

@@ -0,0 +1,7 @@
+<div class="email-action">
+  <table role="presentation" border="0" cellpadding="0" cellspacing="0" width="100%" class="email-btn-table framework-extra"><tr><td class="email-btn-row"><a href="{{.URL}}" class="email-btn">{{.Label}}</a></td></tr></table>
+  <table role="presentation" width="100%" cellpadding="0" cellspacing="0" border="0" class="email-link-box"><tr><td class="email-link-cell">
+    <p class="email-link-label framework-extra">{{.Hint}}</p>
+    <p class="email-link-url"><a href="{{.URL}}">{{.URL}}</a></p>
+  </td></tr></table>
+</div>