WAL Replay counter

[owen-d]

This PR introduces an alternative method for skipping WAL entries during replay which have already been recovered via checkpoints. Previously, we took advantage of out of order errors to "skip" old logs until we saw new data. In preparation for removing the ordering constraint, we now include a per stream counter which:

1. increments on every accepted entry
2. resets after WAL recovery

This annotates WAL records with the counter value for their most recent entry and during replay the stream will skip any counter value less than or equal to it's own (which is recovered via checkpoint). This ensures that even once we enable out of order log ingestion, we won't duplicate writes that occur in both checkpoints and segments.

This includes the following metric (localhost example after a WAL recovery)

# HELP loki_ingester_wal_duplicate_entries_total Entries discarded during WAL replay due to existing in checkpoints.
# TYPE loki_ingester_wal_duplicate_entries_total counter
loki_ingester_wal_duplicate_entries_total 656

[cyriltovena]

LGTM

[owen-d]

ref #1544