feat(pebble): support pinning `FormatMajorVersion` (#10789)

* Upgrade to pebble v2.0.3 - Configure latest pebble database format at init - Do not automatically ratchet database format if set in config - Daemon messge about new available pebble format - Document pebble config with formatMajorVersion - Add warning to users running badger, nudging them to switch to flatfs or pebble - docs: explain Pebble's `FormatMajorVersion` - Use pebbleds instead of badgerds in t0060-daemon.sh - Print badgerds warning message to stderr