Add regex pattern to IRI class

[korikuzma]

An IRI is a reference to another object. It can be of any form under the IETF specification. When we say the sequence slot is dereferenced, it means that instead of an IRI, we have a SequenceReference object. This is true for every property in VRS where we allow for an IRI or object.

I think it is fair for us to assume this property (and every property) is dereferenced / has full object representation for normalization. We SHOULD NOT assume that an IRI takes a specific form (e.g. a refseq or ga4gh identifier) as we do here. I also believe that IRIs that contain a colon before an IRI fragment identifier (#; again, as seen here) are not valid IRIs.

Originally posted by @ahwagner in #234 (comment)

[github-actions]

This issue was marked stale due to inactivity.

[Rhythm1710]

Hi! Can I work on this issue?

[korikuzma]

@Rhythm1710 Go for it!