virt-aa-helper: Add support for smartcard host-certificates

virt-aa-helper: Add support for smartcard host-certificates

When emulating smartcard with host certificates, qemu needs to
be able to read the certificates files. Add necessary code to
add the smartcard certificates file path to the apparmor profile.

Passthrough support has been tested with spicevmc and remote-viewer.

v2:
- Fix CodingStyle
- Add support for 'host' case.
- Add a comment to mention that the passthrough case doesn't need
  some configuration
- Use one rule with '{,*}' instead of two rules.

Signed-off-by: Arnaud Patard <apatard@hupstream.com>
Reviewed-by: Cole Robinson <crobinso@redhat.com>
Acked-by: Christian Ehrhardt <christian.ehrhardt@canonical.com>