#### Problem
The current RocksDB read/write perf metrics do not include the total operation nanos
and thus we have to include all fields that might contribute to the total operation nanos.
#### Summary of Changes
This PR includes the total operation nanos in RocksDB's read/write perf and reduces the
number of reported fields in its perf metric.
#### Problem
When the number of RocksDB read/write operations spikes, its payload size
might exceed the limit (413 Payload Too Large).
#### Summary of Changes
This PR rate-limit the perf-sampling of RocksDB read/write operations by one second
in addition to the existing sampling that is configurable via the hidden validator
argument --rocksdb-perf-sample-interval.
#### Problem
After #25042, each LedgerColumn has its own BlockstoreRocksDbWritePerfMetrics
and BlockstoreRocksDbReadPerfMetrics instances. As it has total ownership,
its member field does not need to use Arc.
#### Summary of Changes
Change perf_samples_counter from Arc<AtomicUsize> to AtomicUsize
under BlockstoreRocksDbWritePerfMetrics and BlockstoreRocksDbReadPerfMetrics.
#### Problem
LedgerColumnOptions contain two fields, perf_read_counter and perf_write_counter,
that are not really options but internal counters.
#### Summary of Changes
This PR introduces BlockstoreRocksDbPerfSamplingStatus, a struct that holds internal
status for RocksDB perf sampling and moves perf_read_counter and perf_write_counter
out from LedgerColumnOptions.
#### Problem
blockstore_db.rs becomes bigger.
#### Summary of Changes
Move BlockstoreRocksDbColumnFamilyMetrics to blockstore_metric.rs out from blockstore_db.rs.
#### Problem
blockstore_db.rs becomes bigger.
#### Summary of Changes
Move trait ColumnMetrics and metric-macros to blockstore_metric.rs out from blockstore_db.rs.
#### Problem
blockstore_db.rs becomes bigger.
#### Summary of Changes
This PR creates blockstore_metric.rs and moves metric-related functions out from blockstore_db.rs.