Sometimes plugins need to have additional data or options available
when rendering custom markdown features/rules that are not available
on the default opts.discourse object. These additional options should
be namespaced to the plugin adding them.
```
Site.markdown_additional_options["chat"] = { limited_pretty_text_markdown_rules: [] }
```
These are passed down to markdown rules on opts.discourse.additionalOptions.
The main motivation for adding this is the chat plugin, which currently stores
chat_pretty_text_features and chat_pretty_text_markdown_rules on
the Site object via additions to the serializer, and the Site object is
not accessible to import via markdown rules (either through
Site.current() or through container.lookup). So, to have this working
for both front + backend code, we need to attach these additional options
from the Site object onto the markdown options object.
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}]
...
```
