[ovirt] Collect engine tunables and domain information.

Currently sos does not capture engine-config values or domain information.
We should capture both of these as the tunables can help in troubleshooting.

Similarly the domain information can help track AD/IPA issues.

These can currently be dug out from the DB dump, however having them in a plaintext
file makes checking these much faster and easier, and a DB is not always available.

Signed-off-by: Jake Hunsaker <jhunsake@redhat.com>