Put our link to all mails and sync the formatting

src/mail_templates/app_update_available.ejs

@@ -1,18 +1,17 @@
 <%if (format === 'text') { %>
 
-Dear Admin,
+Dear Cloudron Admin,
 
-A new version <%= updateInfo.manifest.version %> of the app '<%= app.manifest.title %>' installed at <%= app.fqdn %> is available!
+a new version <%= updateInfo.manifest.version %> of the app '<%= app.manifest.title %>' installed at <%= app.fqdn %> is available!
 
 The app will update automatically tonight. Alternately, update immediately at <%= webadminUrl %>.
 
 Changes:
 <%= updateInfo.manifest.changelog %>
 
-Thank you,
-your Cloudron
+
+Powered by https://cloudron.io
 
 <% } else { %>
 
 <% } %>
-