## Motivation
Prior to this PR we've been using `sled` as our database for storing persistent chain data on the disk between boots. We picked sled over rocksdb to minimize our c++ dependencies despite it being a less mature codebase. The theory was if it worked well enough we'd prefer to have a pure rust codebase, but if we ever ran into problems we knew we could easily swap it out with rocksdb.
Well, we ran into problems. Sled's memory usage was particularly high, and it seemed to be leaking memory. On top of all that, the performance for writes was pretty poor, causing us to become bottle-necked on sled instead of the network.
## Solution
This PR replaces `sled` with `rocksdb`. We've seen a 10x improvement in memory usage out of the box, no more leaking, and much better write performance. With this change writing chain data to disk is no longer a limiting factor in how quickly we can sync the chain.
The code in this pull request has:
- [x] Documentation Comments
- [x] Unit Tests and Property Tests
## Review
@hdevalence
* Create and mount persistent disk to store zebrad state, update runner container config to use
* Enable checkpoint sync in zebrad image config
* Lower state memory cache from 500MB to 50MB
* Upgrade host to n2-standard-4
* Bump zebrad-cache disk size to 100GB
* Copy zebrad as the tests are compiled with a hardcoded path to it
* Rename all debug binaries for easy invocation
* Name state cache disk, use the correct path to binaries
* Create volume and all that jazz on instance creation
Otherwise there's a lot of on-instance commands to do that is just handled by this shortcut.
* Explicitly mount the state cache and cleanup test instance
* Wait for zebra-test container to start then attach
* Always clean up even if the tests step fails
* Keep fast sleep but only print 'waiting' once
* attempt to use zcashconsensus crate in zebra-script
* boop
* update verify fn to use zebra types
* a bit more cleanup
* cleanup
* more
* beep boop
* fix renamed member
* cleaning
* get a real branch id
* remove as of yet unneeded api
* Update zebra-chain/src/transaction.rs
* Update zebra-chain/src/transaction.rs
* more cleanup
* oops wrong dep section
* use a tuple to communicate arg association
* update to use published version of zcash_script
* fix new compiler error
* install llvm on windows
* fix bindgen bug????
* try to get docker file to win
* okay try everything
* fix windows build maybe
* always download choco
* fix paths for moved types
* try a different error message
* try convenience script
* try installing just llvm
* add back one more
* try installing some headers
* try a diff package
* try everything
* remove the minimum
* try newer docker builder image
* cleanup docker image
* cleanup extra ci step
* Add CI workflow similar to other zebra
* Bump cache TTL to 24hours
* Expand image name to include full repo owner/repo-name/branch-name
* Force to lowercase because google container registry demands it
This may not be universally shell compatible
* Use bash as gcloud action container entrypoint
Jane Lusby
Deirdre Connolly