feat: Initial journalling implementation

[bjchambers]

This is part of #841.

• Persistence of batches using Arrow IPC format.
• Journalling and recovery of batches via append-only okaywal crate.
• Concatenating batches to produce checkpoints (also in IPC format)
• Recovering from checkpoints
• Concatenating journal checkpoints with in-memory data for execution.

Next steps

• Allow adding checkpointed batches directly (eg., for import from Parquet).
• Allow subscribing to newly added batches (eg., possibly replacing existing in-memory implementation).

Future work:

• Handle late data by merging with overlapping in-memory and possibly checkpointed batches.
• Checkpoint to object store / read checkpoints from object stores. May lead to moving checkpoint storage to Parquet, even while using IPC for the write-ahead log.