documentation cleanup

Splitting this from #1356 

* [ ] Review / rewrite keyholder playbooks #1361 
* [ ] Review / rewrite `playbooks/ORCHESTRATION.md` and `playbooks/snapshot-timestamp-sync.md`
* [ ] make sure the issues that are filed automatically either include the instructions for handling those failures or include a link to documentation 
* [ ] Review / rewrite playbooks for public good instance maintenance