Update documentation about "Active" groups

Summary

1. In the documentation, https://confluence.atlassian.com/crowd/adding-a-group-20807693.html, it mentions this flag correspond to access

   Only deselect this if you wish to deny access to all members of the group.

2. However in this bug report: https://jira.atlassian.com/browse/CWD-4571, it explains otherwise:

   The active/inactive flag of a group does not have any special semantics in Crowd (see CWD-2033). In particular, it does not have any effect on the ability of the group members to authenticate.

3. We checked that this flag will be propagated into applications but up to the application to use it for something (other than authentication purpose)'

Please help with

Clarify what the flag is expected for in the documentation https://confluence.atlassian.com/crowd/adding-a-group-20807693.html