* IconButton: New component to share pointer, size & hover style for icon buttons
* Progress
* IconButton: new component
* Think I am done
* Updated snapshots
* Do not like the black button reverting that, and not the plus-circle changed to plus
* fixed test
* fixed e2e test
* Fixed ts issue
* DatasourceEditor: Add UI to edit custom HTTP headers
Support for custom headers was added in #11643 but was missing in the UI.
Fixes#12779
* Review
* Layout updates
Co-authored-by: Dominik Prokop <dominik.prokop@grafana.com>