v0.3.0-beta

Changelog

• Replaces anyhow and thiserror with a custom error implementation
• Fixes replication by parsing received messages to KVTs instead of message values (the V in KVT)
• Allows setting sled cache capacity via SLED_CACHE_CAPACITY env var
• Friends are now saved to solar.toml when provided via the CLI
• Adds a JSON-RPC server (HTTP) as an actor
  • Exposes ping, whoami and publish methods