Auto-populate the name field before sumitting the Create Media form

[PaulKiddle]

It would be really useful if the Create Media form's name field could be made visible and prepopulated in the file uploader's afterStateUpdated hook, so that users can edit the name before the submit the form.

The majority of our images have extra numbers at the end of their filenames, so this would save up to 50% of form submissions in our workflow.

[awcodes]

The problem is that if it is not using preserveFileNames then there isn't a name until it is saved, since the file gets renamed to a hashed value.

Might be easier to rename the files before uploading them, if that's feasible.

[PaulKiddle]

AFAICT the hash is a uuidv4 so could also be generated in the afterStateUpdated hook if the user is not preserving filenames? (And dehydrateStateUsing for the non-JS case.) It shouldn't matter if this value is generated before or after form submit.

RE: Renaming before upload, unfortunately this is a hard requirement from my product manager, I can't influence the users' workflow.

[PaulKiddle]

@awcodes I have proposed a PR to add this functionality, I would appreciate if you could take a look #571