Implement https://meta.wikimedia.org/wiki/Schema:ExternalLinksChange
The Wikipedia Library needs to be able to produce reports about the insertion and removal of links in Wikipedia. Regretfully, the `externallinks` table does not record changes -- only status.
Implementing this schema would make it much easier for them to produce the necessary reports and would enable historical analyses. It will also be incredibly valuable to the Wikimedia community for anti-spam efforts.
**Progress summary:**
- @Legoktm has implemented the schema using data from the spam blacklist. This data is logged in the ExternalLinksChange eventlogging table.
- Data collection is currently live on test wiki
- There is an outstanding bug whereby links are not being recorded. It's not clear why this is (there's currently no clear pattern), though it could be a result of spam blacklist optimization.