1129 enketo api call from cljs

Closes #1129 by moving the rendering of the `Add Submission` button from clj to cljs.
Note that we went ahead and inserted the `fact` macros in `datasets_test.clj`. Would recommend reviewing that diff with the [&w=1](https://github.com/blog/967-github-secrets) option.
Also note: `OO` = @okal!