Allow a tab_overrides in config.SECRET.json

[jkomoros]

Currently if you want to override tabs you have to fully override it, expanding out the default tabs manually.

Hav a separate config field of tab_overrides, an object like:

{
  before: {
    'default_end_tabs': {
       //tab config item
       collection: 'everything/working-notes'
     }
  },
  after: {
  }
}

When expanding read left to right and if the current item is an “expand” or named something that has an item in the map then insert it before or after. (And anything that has been inserted has to be reexpanded)

Allow items to be strings which are equivalent to {expand:”STRING”}

And update the production config (on both machines)

[jkomoros]

• [x] Make it so inject-config pulls through tab_overrides
• [x] Make it so selectors wires through tab_overrides
• [x] tabConfiguration should actually work with tabOverrides
• [x] Update README
• [ ] Update production config on MP, MBP, K

[jkomoros]

Done as of 7b77861