playbooks: add tip on pod failures, group general tips together

Created by: bobheadxi

Currently debugging a crashloopbackoff on k8s.sgdev.org where prometheus is failing to start using GCP, and I suddenly remembered that GCP is not very useful for this stuff because it doesnt seem to tell you why something might be restarting - CrashLoopBackoff seems to probably be the most common way issues present themselves, so I added a bit at the top of the playbook.

Also reorganized the sections a bit with the more general types of issues at the top, and consolidated some of the kubectl tips into the kubernetes section in deployments.

Also updated note on Jaeger - it is now available directly at https://sourcegraph.com/-/debug/jaeger