Issues found by Troy when using create-iot-react-app

[troyibm]

Here's a list of issues I ran across when using the create-iot-react-app.

1. I think yarn is required. The docks sounded like npm could be using instead. That should be documented somewhere (or just use yarn in the docs so it is implied more).

2. I think the node version required is 10.15.3.
   I had node 9.11.2 installed and when I ran it I got error @typescript-eslint/eslint-plugin@2.24.0: The engine "node" is incompatible with this module. Expected version "^8.10.0 || ^10.13.0 || >=11.10.1". Got "9.11.2".
   When I installed the latest node version and ran it, I got `error carbon-addons-iot-react@2.77.3: The engine "node" is incompatible with this module. Expected version "10.15.3". Got "12.16.3"

3. Hit javascript heap max memory when doing yarn build. FATAL ERROR: CALL_AND_RETRY_LAST Allocation failed - JavaScript heap out of memory.
   I had to export env var NODE_OPTIONS=--max-old-space-size=4096 in order to get build working.