Provide forward joins to Identification, Protocol, Provenance and UsagePolicy #152
Description
Use cases have been presented for multiple UsagePolicies per entity from Local Contexts. Based on this and the commentary to keep join tables in DwC-DP, we should add foreign keys from resources that connect to the UsagePolicy, Protocol, and Provenance tables wherever they are missing. Specifically,
Material.usagePolicyID
Media.usagePolicyID
Event.provenanceID
Material.provenanceID
Media.provenanceID
Event.protocolID
Identification.protocolID (this suggestion from tdwg/dwc#774)
Material.protocolID
Occurrence.protocolID
Survey.samplingProtocolID