Update to create-react-app 4

- had to update eslint deps
- ran into https://github.com/palantir/blueprint/issues/4112
- had to move beta.svg out of static/
- had to fix prettier formatting changes
- ran into https://github.com/facebook/jest/issues/7780

tsconfig.json

@@ -15,7 +15,8 @@
         "noEmit": true,
         "jsx": "react",
         "downlevelIteration": true,
-        "experimentalDecorators": true
+        "experimentalDecorators": true,
+        "noFallthroughCasesInSwitch": true
     },
     "include": ["src", "test"]
 }