As a mismatch reviewer
I want to know the external source that Wikidata is mismatching against
in order to be able to investigate the mismatch further
**Problem:**
We need to show a new column in the results table that lists the name of the external source and optionally provides a link to it. In order to do that we need to augment the upload meta data with a field for the name of the external source (required) and a link to the external source (optional).
**Screenshots/mockups:**
{F34619618}
**BDD**
GIVEN a results page
WHEN viewing the results table
THEN there is a column to indicate the source for each mismatch
**Acceptance criteria:**
[ ] upload metadata is augmented to require the name of the external source (e.g. imdb) and optionally a link to the external source (e.g. https://imdb.com)
[ ] upload documentation is updated with info about new metadata
[ ] results table has a column for the external source
[ ] external source column shows the external source of the mismatch
[ ] the name of the external source is linked if the upload metadata contains the external source link