Bad document reporting

[fjalir]

Implement a public page which can be used to report bad documents.
The user must enter (document.id or document.barcode) and a reason for the report.
The page should explain where the user can find document.id or document.barcode.
The page may show the metadata of the document to verify the input.

Reported documents must be shown on the "DB-Admin".
There may be a special page to review reported documents by our staff.

[cbdevnet]

Maybe collapse into #193 ?