refs #9865
- removed all `oauth2` and token-based ESA auth
- added new `cookie` authenticator which handles session creation
- updated the session store to extend from the `ephemeral` in-memory store and to restore by fetching the currently logged in user and using the success/failure state to indicate authentication state
- ESA automatically calls this `.restore()` method on app boot
- the `session` service caches the current-user query so there's no unnecessary requests being made for the "logged in" state
- removed the now-unnecessary token refresh and logout routines from the `application` route
- removed the now-unnecessary token refresh routines from the `ajax` service
- removed `access_token` query param from iframe file downloaders
- changed Ember Data adapters and `ghost-paths` to use the `/ghost/api/v2/admin/` namespace
refs https://github.com/TryGhost/Ghost/issues/9724
- fixed Card menu plus icon's rounded edges
- decreased link toolbar appearance delay
- changing 'H'/'h' toolbar mapping to 'H2'/'H3' and harmonized title font size
refs https://github.com/TryGhost/Ghost/issues/9724
- added `{{koenig-basic-html-input}}` component
- uses a stripped down version of Koenig
- supports all inline formatting that Koenig supports
- supports inline text expansions
- supports inline key commands
- limited to a single paragraph
- serialises and deserialises from HTML rather than mobiledoc
- updated `{{koenig-caption-input}}` to use `{{koenig-basic-html-input}}`
- updated image and embed cards to calculate word counts correctly for html captions
- bumped Spirit dependency to fix styling of toolbars within the editor canvas
- fixed positioning in toolbar components to account for `parentElement` not necessarily being the closest element to position against
refs https://github.com/TryGhost/Ghost/issues/9724
- fixed image card background colour
- made placeholder illustration for image cards work with Night Shift
- added viewbox prop to `summer.svg` illustration
- bumped ghost-spirit dependency
- fixed link discoverability when spellcheck is on
- fixed list spacing after headings 3-6 and refined list line heights
- added quick transition to format toolbar chiclet
- removed minimum width for image caption
- fixed wide image width in Safari
refs https://github.com/TryGhost/Ghost/issues/9724
- add `ember-useragent` package so that we can check the user agent screen for known-incompatible browsers/devices
- show alerts for Edge, mobile browsers, and IE11 when accessing the editor with Koenig enabled
