.ernrc formatting

[belemaire]

Right now .ernrc JSON file is not really formatted, it's just one line of JSON which makes it less human readable.

We should write .ernrc file as a formatted/indented JSON, as we sometime have to look at it / edit it manually.

i.e

From

{"platformVersion":"1000.0.0","cauldronRepositories":{"benoit":"https://github.com/belemaire/dev-cauldron.git","benoitwalmart":"git@gecgithub01.walmart.com:blemair/my-cauldron.git"},"loglevel":"debug","miniAppsLinks":{},"cauldronRepoInUse":"benoit"}

To

{
  "platformVersion": "1000.0.0",
  "cauldronRepositories": {
    "benoit": "https://github.com/belemaire/dev-cauldron.git",
    "benoitwalmart": "git@gecgithub01.walmart.com:blemair/my-cauldron.git"
  },
  "loglevel": "debug",
  "miniAppsLinks": {},
  "cauldronRepoInUse": "benoit"
}