Add relevant occurrence API information to encourage occurrence citations

[CecSve]

Feedback on Maps API (Github source for this page)

Currently, the section about the Map API does not specify that the underlying data comes from the occurrence search API. We occasionally receive questions on help desk on how to cite maps correctly and we always encourage users to cite the underlying data through a data download.

Could we add something along the lines of this:

Species occurrences represented on the maps are based on the occurrence search API. To properly attribute the original data holders of the generated maps, please use the occurrence download API (API users can use the API download) to generate a download of the underlying data and generate a citeable DOI.

We should probably add information about citing the maps themselves too.

UPDATE: A website that use the map API display maps that are updated and the download and citations would be for a given point in time.

relevant (old but still open) issue gbif/portal-feedback#59 and gbif/portal16#624.