* use uuid for generated containers
* use dynamic titles based on container views
* add icons to built-in views

fixes #85975

* wip 2

* use viewlet stubs

* fix layering issue

* fix saveState and contextmenus

* move context menu logic into panecomposite

* revert tasks.json

* tasks again

* add showHeaderInTitleWhenSingleView values

* patch tests

* some cleanup

* more cleanup

* start view

* merging conflicts

* fix title and dnd

* adding missing api surface to pane composite

* additional merge resolution

* rename splitview panels to panes

* rename files

* customViewPane

related to #78168

Emitters should generally not be reassigned as their corresponding event would also be lost. Marking these as readonly just to enforce this