Add support to pipeline entire interfaces using an abstraction

[mkorbel1]

Motivation

If modules leverage ROHD's Interfaces and want them propagated through a Pipeline abstraction in ROHD, it requires the user to generate per-port connectivity through the Pipeline and reconstruct per-stage Interfaces. It would be nice if the Pipeline abstraction could take care of this automation.

Desired solution

Add to or extend functionality of Pipeline to support pipelining Interfaces.

Alternatives considered

We could leave users to manually perform this themselves, which gives more flexibility but also more overhead.

Additional details

One tricky thing is that constructing a "matching" interface per-cycle depends on the Interface implementation. Perhaps this development should be paired with something like an upgrade to Interface that requires a "match" method. Maybe something from #36 could be useful.