switch to blueprintjs UI toolkit

package.json

@@ -3,6 +3,7 @@
     "version": "0.1.0",
     "private": true,
     "dependencies": {
+        "@blueprintjs/core": "^3.28.1",
         "@pybricks/firmware": "2.0.0",
         "@pybricks/mpy-cross-v5": "^1.0.0",
         "@shopify/react-i18n": "^4.0.0",
@@ -15,23 +16,20 @@
         "@types/react": "^16.9.35",
         "@types/react-dom": "^16.9.8",
         "@types/react-redux": "^7.1.9",
-        "@types/react-transition-group": "^4.4.0",
+        "@types/react-splitter-layout": "^3.0.0",
         "@types/redux-logger": "^3.0.8",
         "@types/web-bluetooth": "^0.0.6",
         "ace-builds": "^1.4.9",
-        "bootstrap": "^4.5.0",
         "file-saver": "^2.0.2",
         "jszip": "^3.4.0",
         "node-sass": "^4.14.1",
         "react": "^16.13.1",
         "react-ace": "^9.0.0",
-        "react-bootstrap": "^1.0.0",
         "react-dom": "^16.13.1",
         "react-dropzone": "^11.0.1",
         "react-redux": "^7.2.0",
-        "react-resize-observer": "^1.1.1",
         "react-scripts": "3.4.1",
-        "react-transition-group": "^4.4.1",
+        "react-splitter-layout": "^4.0.0",
         "redux": "^4.0.5",
         "redux-logger": "^3.0.6",
         "redux-observable": "^1.2.0",