Delete write_eml()

[peterdesmet]

Suggested in camtraptor July 2023 coding sprint

write_eml() and write_dwc() were developed to convert Camtrap DP to Darwin Core Archives, which could then be uploaded to the IPT. Now that the IPT supports the publication of Camtrap DP (data + metadata) natively, there is limited need for the EML conversion. Rather, we should help users in reading (cleaning and writing) Camtrap DP files.

The write_dwc() function however is still needed, as it will be used by GBIF to convert Camtrap DPs published through the IPT to Darwin Core data that can be ingested as occurrences. GBIF does not use the write_eml() function, but will directly parse the datapackage.json metadata to their metadata registry. Removing the write_eml() function from camtraptor frees up time to develop, maintain and write tests for other functions.

Users who want to publish their camera trap data from Camtrap DP to Darwin Core still can by:

1. Loading their Camtrap DP export with read_camtrap_dp()
2. Using write_dwc() to convert the data (or do it using their own transformation)
3. Uploading the files to the IPT
4. Manually adding the EML metadata

[damianooldoni]

write_eml() is developed in camtrapdp package (see https://inbo.github.io/camtrapdp/reference/write_eml.html). At the moment no need to reexport it in camtraptor.