Make it possible to change User management settings post install

[jdaviescoates]

One often gets into somewhat of a pickle by installing an app with the wrong user management settings.

It'd be great if it were possible to reset these settings on already installed apps (imho even if doing so was a bit hacky with warnings)

[girish]

Practically all apps won't handle it properly if you add/remove LDAP dynamically. You have to basically go and tinker with the database to move over users from ldap to local and vice versa. It's currently this way just to keep our support overhead low.

Like the immediate question after we add this is: how can I migrate LDAP users of xxx as local This is impossible for us to support.