Adds suffix to enum methods and changes `in_groups` to
`of_groups`

Model.new.attributes now also returns encrypted attributes.

Both of these were related to groups:

1. We need to preload routes (using the `with_route` scope) if we're
   going to get the group's path.
2. We were counting each group's members separately.

They're in the same commit because the spec for N+1 detection wouldn't
pass with only one of these fixes.

Determined by running the script:

```
included = `git grep --name-only ShellAdapter`.chomp.split("\n")
used = `git grep --name-only gitlab_shell`.chomp.split("\n")
included - used
```

This whitelists all existing offenses for the various CodeReuse cops, of
which most are triggered by the CodeReuse/ActiveRecord cop.

Partially addresses #47424.

Signed-off-by: Rémy Coutable <remy@rymai.me>