Add lint process for verifying CPAN uploads table

[preaction]

The CPAN uploads table has some duplicate data in it: There are dist+version combinations that appear more than once. This is a problem that we have to fix in the upload scan process, but first we have to identify the data we need to fix.

We should add a runnable module (using Beam::Runnable) that will check this table for invalid data. The module should look for any duplicate dist/version rows and write a report to STDOUT containing the dist, version, upload IDs, release date/time, and author of the duplicate data.

This process should be configured in a container file in etc/container/schema.yml. It should be configured to run daily via cron to detect invalid data as it comes in.