Impl correct handling for L1DABatch sync events

[delbonis]

Correct handling for when we receive new L1 DA checkpoints, including producing sync actions that update the finalized tip in the tip tracker. This is necessarily going to be somewhat limited, since we're not doing full checkpointing yet. But we can put some pieces in place to make that easy to handle when we do support that.

Blocked by

• Properly create L1 segment from sequencer's view of L1 #116

[john-light]

Will be continued in next sprint