Optimized and updated imports in core package.json (rjsf-team#2931)

* Optimized and updated imports in core package.json
- Updated `tsdx` build to also run umd, eliminating the need for the one-off webpack version build
- Deleted the `test-old` and `build-umd` scripts
- Added `@rjsf/utils` to `peerDependencies`
- Removed all of the webpack and cross-env related packages no longer needed for the one-off build
- Also removed `express`, `gh-pages`, `estraverse*` and `husky`
- Updated a bunch of the `peerDependencies` package versions to the latest
- Deleted the now unnecessary `webpack.config.dist.js`

* - Removed `prettier` from `package.json` as it differs from the version used in the main `package.json`
- Ran `cs-format` to fix all of the prettier errors reported by `cs-check`

* - Bumped `prettier` to pickup latest typescript support
  - Switched from `jsxBracketSameLine: true` to `bracketSameLine: false`
- Ran `cs-format` over `playground` as well

Author: heath-freenome

package-lock.json

@@ -17,10 +17,10 @@
   },
   "dependencies": {
     "lerna": "^4.0.0",
-    "prettier": "^1.18.2"
+    "prettier": "^2.7.1"
   },
   "prettier": {
-    "jsxBracketSameLine": true,
+    "bracketSameLine": false,
     "trailingComma": "es5",
     "useTabs": false,
     "semi": true,
@@ -30,6 +30,7 @@
   "homepage": "https://github.com/rjsf-team/react-jsonschema-form",
   "devDependencies": {
     "husky": "^3.1.0",
+    "lint-staged": "^10.1.3",
     "source-map-loader": "^1.1.2",
     "ts-loader": "^8.4.0",
     "tsdx": "^0.14.1",