Added support for username replacement (and password too) for remote …

…SFTP proxy configuration.

Adding in allowed group prefixes functionality (allows you to enable …

…auto mode for groups, but limit creation to just those groups with a matching prefix).

Added functionality for Active Directory groups to be able to have vi…

…rtual folders created for them along with associated configuration options.

Add minimum username length requirement and ability to provide a user…

…name blacklist.

Added some extra logging, along with using reconnect/disconnect for t…

…he LDAP connections (not needed as much for this repository, but I think the changes were necessary for the sftpgo-ldap-http-server repository due to it having a long-lived process with the HTTP server.

Moving strip domains loop to run before the connections loop.

Adding some more notes/details into the README