Remove CI builds/jobs older than X years

Problem to Solve

Allow users to configure removal of older builds/jobs for their namespace or instance.

Questions to Answer

1. What would it look like to remove CI builds (and all its artifacts) older than X years?
2. How could we enable this on gitlab.com? What comms would we need for our users? Would this be a breaking change, and therefore cannot enable til x.0?
3. What if this could be configurable for Self-Managed and Dedicated customers who manage their own data?