samba-tool: Add new command 'samba-tool drs clone-dc-database'

samba-tool: Add new command 'samba-tool drs clone-dc-database'

This command makes a clone of an existing AD Domain, but does not
join the domain.  This allows us to test if the join would work
without adding objects to the target DC.

The server password will need to be reset for the clone to
be any use, see the source4/scripting/devel/chgtdcpass

(Based on patches written with Garming Sam)

Andrew Bartlett

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Signed-off-by: Garming Sam <garming@catalyst.net.nz>
Reviewed-by: Garming Sam <garming@catalyst.net.nz>