refs https://github.com/TryGhost/Ghost/issues/9505
- remove unordered and bullet list icons from the (+) and / menus
- add unordered and bullet list icons to the formatting toolbar
- reorder toolbar icons to match latest design specs
- remove now-unused `replaceWithListItem` actions
refs https://github.com/TryGhost/Ghost/issues/9311
- adds `{{koenig-slash-menu}}` component that renders a quick-access card/block menu when typing `/` at the beginning of a new paragraph
refs https://github.com/TryGhost/Ghost/issues/9311
- add a mousemove event handler that shows the (+) next to blank paragraphs when the pointer is over them
- fix sticky button when adding a card mid-document by hiding it, we get another `didReceiveAttrs` call with the new range when adding a blank paragraph so it's still shown in that situation
- fix the incorrect button position when adding a card at the bottom of the doc by re-positioning in the next runloop. Problem seems to stem from the component card being rendered after we get the new range so our position calculations are out of sync
refs https://github.com/TryGhost/Ghost/issues/9311
- re-implement the (+) card/list selection menu from the old Koenig alpha with improved positioning and event handling
- buttons work for the currently available cards - `<hr>` and `markdown`
