Update the default file carver block size to be compatible with MySQL 8
& S3.
Update surrounding docs.
Various other updates to references of MySQL versions (all terraform
deploys are now defaulted MySQL 8 in AWS)
# Checklist for submitter
If some of the following don't apply, delete the relevant line.
- [X] Changes file added for user-visible changes in `changes/` or
`orbit/changes/`.
- Add endpoints for osquery to register and continue a carve.
- Implement client functionality for retrieving carve details and contents in fleetctl.
- Add documentation on using file carving with Fleet.
Addresses kolide/fleet#1714
* Use YAML anchors to avoid repeating config blocks
* Use docker volumes to persist data for mysql
* Allow setting `FLEET_SERVER` (fixes#2127) when using the docker-compose file to spin up multiple osquery clients
