ubuntu template: if a user is bound in, don't define ubuntu user
ubuntu template: if a user is bound in, don't define ubuntu user

It might have a conflicting uid, and isn't needed.  Also put the bound user
into sudo group.

Signed-off-by: Serge Hallyn <3df611b026e4639bee8aef7a4beb2e39fcebb313@ubuntu.com>

ostap/lxc,ostap/lxc