Allow for ProteinComponent (or really any "multi-molecule" Component) to be converted to either an Interchange object or an OpenFF Topology

[IAlibay]

Currently we can turn things into an OpenMM Topology (which is great), but we should try to find a way to also allow for a path where we convert mullti-molecule Components to OpenFF Interchange or Topology objects.

[dotsdl]

Moving to milestone 1.5 to focus effort on development docs.

[atravitz]

discussed offline - @IAlibay: converting through rdkit works most* of the time (issues with chirality tags), but we will want to revisit this when deciding how we want to handle pdb loaders.