Convert installation to Bootstrap design

* Refactor client-side validation to be Bootstrap/HTML5 compatible
* Update style of backup/export pages
* Upgraded detect_timezone.js to jstz-1.0.4.min.js, to bring in 3 years' worth of updates
* Replace older jquery.validate.js in installation with jqBootstrapValidation.js (older validate still used in registration flow)
* Update necessary tests for copy changes in installation screens