Notebook views UI (#13914)

* Add notebook editor

Introduce notebook editor component to allow for separate notebook displays in order to accomodate notebook views

* Localize notebook views configuration title

* Refactor view mode and remove the views configuration while it is unused

* Only fire view mode changed event when the value has been changed

* Remove notebook views contribution

* Add metadata capabilities

* Notebook views definitions

* Add notebook views models

* Views test

* Rename type arguments

* Additional tests

* Fix unused import

* Notebook views changes

* Add notebookviews.css

* Update notebookViewModel.ts

* Add cell toolbar styles

* Upgrade gridstack

* Add gridstack styles

* Remove ununsed references

These are part of the next PR and not available yet

* Remove gridstack static file

* Add gridstack as a module in the electron unit tests

* Spacing fixes

* Add copyright notice

* Remove commented code

* Spacing fixes in notebook styles

* Move handle svg to image

* Add typing for gridstack

* Move notebook styles to file

* Rename selector constant

* Rename grid css file

* Add nb-grid-stack class to views grid

* Cell toolbar style adjustments

* Remove unused imports

* Update .eslintrc.json

* Fix outdated instantiation of LabeledMenuItemActionItem

* Address feedback

* Fix from update to main

package.json

@@ -76,6 +76,7 @@
     "chart.js": "^2.9.4",
     "chokidar": "3.5.1",
     "graceful-fs": "4.2.3",
+    "gridstack": "^3.1.3",
     "html-query-plan": "git://github.com/kburtram/html-query-plan.git#2.6",
     "http-proxy-agent": "^2.1.0",
     "https-proxy-agent": "^2.2.3",