Batch all available app updates in updatechecker

src/mail_templates/app_updates_available.ejs

@@ -0,0 +1,54 @@
+<%if (format === 'text') { %>
+
+Dear Cloudron Admin,
+
+<% for (var i = 0; i < apps.length; i++) { -%>
+A new version <%= apps[i].updateInfo.manifest.version %> of the app '<%= apps[i].app.manifest.title %>' installed at <%= apps[i].app.fqdn %> is available!
+
+Changes:
+<%= apps[i].updateInfo.manifest.changelog %>
+
+<% }} -%>
+
+<% if (!hasSubscription) { -%>
+*Keep your Cloudron automatically up-to-date and secure by upgrading to a paid plan at* <%= webadminUrl %>/#/settings
+<% } -%>
+
+Powered by https://cloudron.io
+
+Sent at: <%= new Date().toUTCString() %>
+
+<% } else { %>
+
+    <center>
+
+    <img src="<%= cloudronAvatarUrl %>" width="128px" height="128px"/>
+
+    <h3>Dear <%= cloudronName %> Admin,</h3>
+
+    <div style="width: 650px; text-align: left;">
+<% for (var i = 0; i < apps.length; i++) { -%>
+        <p>
+            A new version <%= apps[i].updateInfo.manifest.version %> of the app '<%= apps[i].app.manifest.title %>' installed at <a href="https://<%= apps[i].app.fqdn %>"><%= apps[i].app.fqdn %></a> is available!
+        </p>
+
+        <h5>Changelog:</h5>
+        <%- apps[i].changelogHTML %>
+
+        <br/>
+<% } -%>
+
+        <% if (!hasSubscription) { %>
+        <p>Keep your Cloudron automatically up-to-date and secure by upgrading to a <a href="<%= webadminUrl %>/#/settings">paid plan</a>.</p>
+        <% } %>
+
+        <br/>
+    </div>
+
+    <div style="font-size: 10px; color: #333333; background: #ffffff;">
+        Powered by <a href="https://cloudron.io">Cloudron</a>.
+    </div>
+
+    </center>
+
+<% } %>