feat: raft log auto compaction

Summary

• feat: raft log auto compaction

Add alter system cluster_wal_max_size and cluster_wal_max_count parameters which control the auto compaction of _raft_log system space based on the size in bytes and number of tuples respectively.

• fix: bug in capacity calculations in RaftSpaceAccess::entries

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• Close #315 (closed)
• Cherry-pick to: none / 24.6
• Docs follow-up: new issue
• Changelog is updated