Implement TypedUri from isodoc-models

[ronaldtse]

As described here, https://github.com/riboseinc/isodoc-models/issues/30,

TypedUri now takes a type. In our case, an IsoBibliographicItem has the following links:

• "Online browsing platform", we can use the type via to indicate that this is one of the data sources.
• "About the standard page", we can use the type about to indicate that this link provides information "about" the standard.
• RSS: there is no link type indicating a link for updates. Maybe we use news for now?

[ronaldtse]

https://github.com/link-relations/registry/issues/2

[opoudjis]

Btw, type is optional, but in the URI's you're dealing with, you're going to have to populate it.