Track latest supported logging configurations in elastic/logs

[DJRickyB]

Using the code added for #281, we should remove static assets from elastic/logs and instead prefer the ones we can get from https://github.com/elastic/package-assets. This should mean removing a bunch of jinja and focusing on dynamic retrieval per the mechanisms that are in place now.

Required packages for parity:

• kafka
• nginx
• apache
• mysql
• kafka
• redis
• system

One ambiguous thing to handle is going to be the so-called application-logs integration, which is not an integration at all but seems to be some carryover filebeat/libbeat data. We may want to leave it behind at this point, provided its absence doesn't wildly change the profile of the benchmark.

High level steps:

• Onboard target integrations to package-assets workflow for publishing (from production package-storage, as a start)
• Change the track to use these integrations, testing for functional badness with our old-ish data but also drastic, unquantifiable performance differences

Follow-up to include generating or gathering more up-to-date seed data for the corpora

[michaelbaamonde]

Quick update: I'm chipping away at this with a local copy of package-assets. There are a few gotchas so far, but the overall strategy seems like it's going to work out. I should have a PoC with a subset of the logging track to share shortly.