Download file from inside resource's DwC-A

[diogok]

It would make access to data easier if one could download a specific file from the generated archive, instead of download the whole archive and unpacking, specially for automated tools.

This is an idea to add a URL to do that:

http://localhost:8080/archiveFile.do?r=tes1&f=vernacularname.txt

[kbraak]

Thank you for taking the time to contribute this pull request @diogok. Please create a new issue to raise the visibility of this enhancement request. When doing so, please be sure to explain the rationale / use cases for it as well. That way it is more visible and understandable to the wider community and can be voted on. Thanks.