Feature/ingest folder

[Daniel-KM]

Sometime users want to import some hundreds files for one item, for example all images of a scanned manuscript, so to select the directory is a lot simpler.

[Daniel-KM]

The pr is based on previous one because it fixes the same issue, but it can be separated if needed.

[AlyxTaj]

The people who create items one by one at our library are not usually very tech savy. On Omeka Classic, they used to select all the documents from one repertory to upload them and that was it. This was essential when dealing with documents of hundreds of pages.
Now that we're moving to Omeka S, the bulk upload of files is going to be missing, and I cannot imagine them creating a CSV file with the list of media to link to an item they have created.
This folder based option to FileUpload would be an amazing improvement for us.

[jimsafley]

I'm currently reviewing this. Please rebase your branch so the changes I merged upstream are updated and don't show up in this PR.

[Daniel-KM]

Yes, it's rebased.

[jimsafley]

I'm wary of the use of "folder" throughout your changes (even the new name). We already use "directory" in this module and others, so I prefer that you change "folder" to "directory."

[Daniel-KM]

I renamed "folder" by "directory" in last commit.

[jimsafley]

I notice that the "Directory" select menu does not include the sideload directory itself. Is there a reason for this?

[jimsafley]

Thank you for this important feature!