Come up with a plan to make past descriptors etc. easier available and queryable (giant database)

We should make past descriptors and other network status documents easier available at least for dev purposes (maybe in a giant database) as this would help a lot with all sorts of tasks (e.g. analyzing bw measurement anomalies, bad-relay work , bwauthealthetc.). This ticket is for all the planning work. Once we've found a good way forward we'll open new tickets for the actual work.