collect, store, view, notify on metrics

[laralove143]

all/most of this can be extracted to a lib, why is this an issue here then? idk

1. collect and store metrics in a db periodically:
   • [ ] gateway latency
   • [ ] discord http latency (#47)
   • [ ] discord http ratelimit hits
2. automate graphs:
   • [ ] create line graphs from all data periodically
   • [ ] serve them over prometheus
3. notify:
   • [ ] periodically check the average of metrics in the last period, if it's above manually set thresholds, execute a webhook
   • [ ] periodically execute a webhook with the prometheus link (basically a reminder)