This is the first release candidate for Garage v0.8.0.

Changes since v0.7.3 include:

- Ability to replace sled with lmdb or sqlite for the metadata storage

- K2V now included in official release builds, still as a technical
  preview (the API is unstable and might be subject to changes)

- Bucket quotas

- Update to Netapp 0.5 with streaming body; stream data blocks to client
  as they are received

- Improved monitoring of background tasks

- Scrub is scheduled automatically, can be paused/resumed/made faster or
  slower at runtime

- Background block resync can be made faster or slower at runtime

- Many computationally-intensive tasks have been moved to dedicated
  tokio threads for blocking tasks

- Reduce lock contention in block manager

- Less sensitive timeouts for RPC operations, avoiding nodes
  deconnecting or requests timing out on slow connections

- Cleaner and better optimized handling of byte chunks with the bytes
  crate

- Many improvements in build system; cargo features for everything

- HTTP servers (S3 API, K2V API, Admin API) are no longer mandatory: by
  removing the corresponding config section, they are simply not started

- pretty_env_logger is replaced by tracing_subscriber::fmt

- Various API fixes

- Fix the build version reported by the CLI

- Fixed builds for non-amd64 platforms

- Provide multi-arch Docker containers

- Avoid using/propagating broken cluster layouts

- Allow for hostnames in bootstrap_peers and rpc_public_addr

- Some documentation updates (not finished yet)