This PR introduces a new option `--reference` that allows users to
filter rules base on rule reference. This is useful to evaluate
compliance with a particular policy requirement.

This feature needs SCAP content to contain reference URI-to-title
mapping within the `xccdf:Benchmark` element. The ComplianceAsCode
content upstream project started to provide this mapping in the SCAP
content recently, starting from 62513c391dc5a3fafd12741bd02565ca0e1e8db2.

To support the easier experience with this feature, also a new option
`--references` to the `oscap info` module has been added, this option
extends the output of the command by listing all available reference
names.

Fixes: https://issues.redhat.com/browse/RHEL-1479

Instead of a segfault we will produce an error message.