Redesign resource tree (#1865)

* start redesign work

* add left padding to all tree nodes

* fiddling with padding

* align tab bar line with first item in resource tree

* final touch ups

* fix a strange password manager autofill prompt

* add keyboard shortcuts

* revert testing change

* nudge messagebar to layout row height

* tidy up

* switch to Allotment to stop ResizeObserver issues with monaco

* refmt and fix lints

* fabric touch-ups

* update snapshots

* remove explicit react-icons dependency

* reinstall packages

* remove background from FluentProvider

* fix alignment of message bar

* undo temporary workaround

* restore refresh button

* fix e2e tests and reformat

* fix compiler error

* remove uiw/react-split

* uncomment selection change on expand

package.json

@@ -46,8 +46,8 @@
     "@types/lodash": "4.14.171",
     "@types/mkdirp": "1.0.1",
     "@types/node-fetch": "2.5.7",
-    "@uiw/react-split": "5.9.3",
     "@xmldom/xmldom": "0.7.13",
+    "allotment": "1.20.2",
     "applicationinsights": "1.8.0",
     "bootstrap": "3.4.1",
     "canvas": "2.11.2",
@@ -98,8 +98,8 @@
     "react-redux": "7.1.3",
     "react-splitter-layout": "4.0.0",
     "react-string-format": "1.0.1",
-    "react-youtube": "9.0.1",
     "react-window": "1.8.10",
+    "react-youtube": "9.0.1",
     "reflect-metadata": "0.1.13",
     "rx-jupyter": "5.5.12",
     "sanitize-html": "2.3.3",