Allow adding a projectId to individual occurrences

[marcos-lg]

This new feature comes from this issue gbif/pipelines#836

[MattBlissett]

This would require us making a GBIF Term for projectID (or rather, moving the internal term to the public terms) and adding it to the DWC Occurrence Core definition.

Or, alternatively, requesting a similar term be added to DWC.

[tucotuco]

Resolution of funders, projects, and any metadata needed for these is an ongoing interest for Darwin Core Data Package. It is being consciously left out pending a complete definition of requirements.