* feat(toolbox) allow any toolbox button to be displayed as main

fixes the previous behaviour where only a certain set of buttons were whitelisted for being displayed in the main toolbar

* code review

* code review - fix avatar icon position

* feat(keyboard-shortcuts): show help in a react dialog

- Move shortcut help dom declaration to a react component
- Let open/close logic be handled by AtlasKit Dialog
- Remove static html for help from index.html
- Consolidate keyboard shortcut css

* squash: use lozenge for key styling

* squash: use different iteration style

* squash: update package-lock for lozenge