* Minor changes

* Changed default panel screenshot name

* Removed default visualization type from `addPanel` config

... which, unless defined, will use the app's default (graph). This is the new approach for plugins which supports annotations.

* Select timezone from dashboard toolbar instead of settings

... and refactored `setDashboardTimeRange` for reuse on other pages via a now more generalized `setTimeRange`

* Added optional annotations to `addDashboard` config

* Added `explore` flow

… which reuses `configurePanel` which is very similar