Enable DwC exports to use a different date format than the database

[grantfitzsimmons]

Is your feature request related to a problem? Please describe.
Currently queries use the database date format, which often differs from the standard ISO 8601 format (yyyy-MM-dd) that is the best practice.

The earliest date-time in a period during which a event occurred. If the event is recorded as occurring at a single date-time, populate both EarliestDateCollected and LatestDateCollected with the same value. Recommended best practice is to use an encoding scheme, such as ISO 8601:2004(E).
Source: http://rs.tdwg.org/dwc/terms.htm#eventDate

xkcd.com

From Jordi at MCNB:

For Darwin Core exports, we must change the date format to yyyy-MM-dd each time we export data, as our defined date format differs from the Darwin Core standard.

Is there a method to specify this date change exclusively for exports, bypassing the need to modify the ui.formatting.scrdateformat setting in the app's Remote Preferences?. I aks about this because if GBIF retrieves data from https://[specify].specifycloud.org/export/rss/ or downloads the zip http://[specify].specifycloud.org/static/depository/export_feed/mcnb-zg-dwca.zip, it will always be in the date format of the system we have, which is dd-MM-yyyy.

Describe the solution you'd like
An attribute should be supported in the export definition (and ideally as an option in the query builder) that determines the date format to use for the export.

Reported By
Museu de Ciències Naturals de Barcelona

Additional context
This has been requested by many users, and arguably should be the default for DwC exports in any context.