966396: Add missing ids in relation tables

Relation tables having its models has to have primary key `id`.
Without it ActiveRecord is not functioning properly. It was causing
nasty errors with malformed SQL statements e.g.
`"content_view_version_environments".""`.

There were two models without ids: RolesUser,
ContentViewVersionEnvironment. Unique index for table
`content_view_version_environments` on columns `content_view_version_id`
and `environment_id` was added.

Org and environment deletion were not working. Missing ids were breaking
deletion of relations to these models.

This was probably causing more problems than the two mentioned.

https://bugzilla.redhat.com/show_bug.cgi?id=966396