There is a concept implementation of adding a document on the webapp

My idea of a workflow would be, the user inputs these inputs (maybe all of them)
and then the importers work in functionself.add_document inserve.py.

Then maybe create a temporary document and serve this document with the document view,
using a modified vwerion of the function

        page = papis.web.docview.html(libname=libname, doc=doc)

where maybe there is a flag that controls that this document is a preliminary temporary document
and the user gets a button to add this document to the database.

I think this kind of workflow would be common in most plugins that intend to add a document.
This case here is a good test in order to see what belongs tocli and to therun funktion
inpapis.commands.add andpapis.commands.update too.

Incidentally, if we really make it to code a reasonable add functionality,
then the webapp would be pretty much usable for a lot of users, and I could present it
alongside the cli in fosdem, so this is quite important for papis IMO to get right.

This is also a chance to work again on the decisions that were made for adding papers,
which I think everyone feels it's well, kind of awkward right now (understandably so).
Related to#367 and other issues.

I'd like to pack most smart importer stuff insmart_importer.py for now, I think this is
sensible.