Provide Bitbucket Server support for Active Directory's "Account Disabled" flag

• Currently, if the user account in AD is Disabled then, while the users are synced in cwd_users, the do not populate the /admin/users.
• There is logic in the code that checks whether the user is_active to populate the page. If inactive, it does not.

This is a suggestion to still populate Users with the disabled accounts, but adding a flag Disabled and not count them toward the license. This is the way this flag is handled, for example, in Confluence and Jira Server.