chore: remove big xpub components (they now live in simplej)
These components are intricately linked to SimpleJ (xpub-collabra) and thus do not belong in the set of reusable components that the PubSweet core represents.
These components are intricately linked to SimpleJ (xpub-collabra) and thus do not belong in the set of reusable components that the PubSweet core represents.