This commit introduces a new site setting "google_oauth2_hd_groups". If enabled, group information will be fetched from Google during authentication, and stored in the Discourse database. These 'associated groups' can be connected to a Discourse group via the "Membership" tab of the group preferences UI.
The majority of the implementation is generic, so we will be able to add support to more authentication methods in the near future.
https://meta.discourse.org/t/managing-group-membership-via-authentication/175950
The color_scheme_id needs to be an integer not a string.
This is one of the failing tests that showed this error:
https://github.com/discourse/discourse/runs/3598414971
It showed this error
`POSSIBLE ISSUE W/: /user_themes/0/color_scheme_id`
And this is part of the site.json response:
```
...
"user_themes"=>[{"theme_id"=>149, "name"=>"Cool theme 111", "default"=>false, "color_scheme_id"=>37}]
...
```
