[change] React 18 support

* Support React 18 concurrency and constraints.
* Add new render / hydrate functions.
* Remove uses of findNodeHandle.
* Expose ability to unmount an application once ran.

Fix #1529
Close #2330

Author: edkimmel

configs/.eslintrc

@@ -2,7 +2,7 @@
   "settings": {
     "react": {
       "pragma": "React",
-      "version": "17.0",
+      "version": "18.0",
       "flowVersion": "0.148.0" // Flow version
     }
   },