This change primarly adds a new `Open with...` entry to the explorer context menu. To do this however, I had to make a few other changes:

- Add a new explorer context key for availible editors
- Moved the editor select prompt into a new function called `openEditorWith`
- Use `openEditorWith` for the new `open with` explorer command as well as for the `reopen with` command

This clarifies that the type is an aggregate over inputs and not editor controls.

* IEditor => IEditorPane

* More panes:
* IVisibleEditor => IVisibleEditorPane
* ITextEditor => ITextEditorPane
* ITextDiffEditor => ITextDiffEditorPane

* imports - remove type alias

* More pane renames
* IEditorService#activeControl => activeEditorPane
* IEditorService#visibleControls => visibleEditorPanes

* More editor renames
* activeTextEditorWidget => activeTextEditorControl
* visibleTextEditorWidgets => visibleTextEditorControls

* add a few more readonly to properties
* move IVisibleEditor closer to IEditor
* remove options accessor from IEditor

#88727

For #70020

fixes #77226
fixes #67366