systemd-systemctl-native: handle Install wildcards

systemd-systemctl-native: handle Install wildcards

Handle the %i wildcard appearing in a dependency in the Install section
of a template unit, e.g.

  $ cat foo@.service

  [Install]
  WantedBy=bar@%i.target

Using the real systemctl something like:

  $ systemctl enable foo@baz.service

will create a symlink in /etc/systemd/system/bar@baz.target.wants.
Detect wildcards in templates and make the appropriate substitution.

Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>