Add repair route

this is specifically for the case where some task failed and user
wants to get it back.

src/eventlog.js

@@ -13,6 +13,7 @@ exports = module.exports = {
     ACTION_ACTIVATE: 'cloudron.activate',
     ACTION_APP_CLONE: 'app.clone',
     ACTION_APP_CONFIGURE: 'app.configure',
+    ACTION_APP_REPAIR: 'app.repair',
     ACTION_APP_INSTALL: 'app.install',
     ACTION_APP_RESTORE: 'app.restore',
     ACTION_APP_UNINSTALL: 'app.uninstall',