"Create Document" page improvements

[michaelrsweet]

The Create Document page needs some love:

• Add support for IPP Registration documents
• "Replaces" should also support replacement of previous working drafts, registrations, etc.
• Can we update the file chooser to support multiple files rather than separate ones for clean, redlined, and editable?
• Can we pre-fill the abstract from the "replaces" document?

[wifiprintguy]

Also needs a way of specifying the working group. And for PWG officers, an "SC working group" might be a way to specify documents that are PWG scope rather than WG scope?

[michaelrsweet]

There is already a "workgroup" chooser, with "Printer Working Group" specifying a scope of PWG-wide/steering committee documents.

I also want to:

• Add pseudo-workgroups for OpenPrinting and other liaison organizations so that we can post OpenPrinting slides, etc. to the /pub/pwg/liaison/ directory.