Improve build tooling (#2775)

* build: upgrade yarn

* build: yarn formatted yarnrc

* docs: documentation update

* build: add version check build step

* build: replace clean/build scripts with just-scripts

* build: use a gulp-based build system

* build: make watch task consistent

* build: move rollup deps to build pkg

* build: remove shx from top, push it into docsite

* build: delete old watch script

* build: remove unnecessary lage command

* build: pkg updates

* build: define changeset

* build: move version check outside of long build loop

* build: move babel plugin to build pkg; break out dotfiles

* build: add plugin-proposal-optional-chaining to babel stack

* build: restore pipeline name to prevent build loops from parent pkg

* build: work on pnp mode

* build: get unit tests running in pnp

* build: yarn config updates

* build: pnpify some sdks, get tests running without a build

* build: describe peer deps more completele in react-dnd

* build: remove unnecessary devDeps from html5-backend; improve peerDeps

* build: remove cra-test

* build: use react 17-rc.3

* build: get docsite running

* build: use yarn zero-install

* build: remove pipeline script

* build: use --topological-dev in build_all

* build: correct hoist-non-react-statics import

* build: remove SDI from react-dnd

* build: revert sdi for now

* build: revert react, get tests running

Author: darthtrevino

.eslintrc

@@ -0,0 +1,30 @@
+{
+  "parser": "@typescript-eslint/parser",
+  "plugins": ["@typescript-eslint", "react-hooks", "no-for-of-loops"],
+  "extends": [
+    "eslint:recommended",
+    "plugin:react/recommended",
+    "plugin:@typescript-eslint/recommended",
+    "prettier",
+    "prettier/@typescript-eslint"
+  ],
+  "settings": {
+    "react": {
+      "version": "16.8"
+    }
+  },
+  "env": {
+    "browser": true,
+    "jest": true,
+    "es6": true,
+    "node": true
+  },
+  "rules": {
+    "no-for-of-loops/no-for-of-loops": 2,
+    "react/prop-types": 0,
+
+    // TODO: re-enable
+    "@typescript-eslint/no-explicit-any": 0,
+    "@typescript-eslint/explicit-module-boundary-types": 0
+  }
+}