Save button updates

*Work in progress*

**Current Status:**

* [ ] Users can visit a page and start hack right away
* [ ] Any time you make a change and try to close without saving, a warning blocks you
* [ ] A button specifically for saving
* [ ] Removed old authentication banner
* [ ] Removed old save failed link (you now have a dedicated button)
* [ ] Finalised style changes
* [ ] Popup the modal before authentication