Fix cache-manager to preserve RocksDB directories in hive/haf caches

Previously, the entire datadir/blockchain directory was excluded from
cache tarballs to save space (~1.7GB block_log files). This also
excluded RocksDB directories like account-history-rocksdb-storage which
contain unique replay state data.

Changes:
- Add _build_blockchain_tar_excludes() that excludes only block_log*
  files while preserving RocksDB directories
- Update hive cache type to use the same exclusion logic as haf
- Call _link_shared_block_log for hive caches on extraction (not just haf)
- Simplify _build_haf_tar_excludes to reuse common logic

This fixes CI failures where hived would exit immediately because
account-history-rocksdb-storage was missing from cached data.