refs https://github.com/TryGhost/Ghost/issues/8464
- fix padding on user actions button
- match user screen heading to other screens
- match app screen headers to other screens, update form styles
- change header link colour to match non-link colour
- fix team acceptance test
- fix canvas top padding so header elements always align
- reduce header font size
refs https://github.com/TryGhost/Ghost/issues/7865
- updates all settings screens to use EC tasks and `gh-task-button` to get save-state save buttons
- removes now-unused `settings-save` mixin
- moves the order of button color CSS so that grey buttons can change to green/red after completing
- removes the heading from `apps-loading` template so that there's no odd flash when loading slack/amp screens directly
refs #5652
- always put button text inside opening/closing helper tag
- only include type if it is 'submit' as button is default
- wrap attributes in double quotes
- Adds gh-view-title component to implement mobile menu button for titles on any page
- Refactors the `content-cover` out into the application template
- Fix various z-index issues with content-cover and gh-alert
- Move `.settings-menu-expanded` application view state from body to `.gh-viewport`
- Unify nav menu / mobile menu actions and code