refactor(table_envs): Unify and remove duplicate variables

[acelyc111]

• Unify variables:

old variable name	unified variable name	value
ROCKSDB_ENV_USAGE_SCENARIO_KEY	ROCKSDB_USAGE_SCENARIO	rocksdb.usage_scenario
ROCKDB_CHECKPOINT_RESERVE_MIN_COUNT	ROCKSDB_CHECKPOINT_RESERVE_MIN_COUNT	rocksdb.checkpoint.reserve_min_count
ROCKDB_CHECKPOINT_RESERVE_TIME_SECONDS	ROCKDB_CHECKPOINT_RESERVE_TIME_SECONDS	rocksdb.checkpoint.reserve_time_seconds
MANUAL_COMPACT_KEY_PREFIX	MANUAL_COMPACT_PREFIX	manual_compact.
MANUAL_COMPACT_DISABLED_KEY	MANUAL_COMPACT_DISABLED	manual_compact.disabled
MANUAL_COMPACT_MAX_CONCURRENT_RUNNING_COUNT_KEY	MANUAL_COMPACT_MAX_CONCURRENT_RUNNING_COUNT	manual_compact.max_concurrent_running_count
MANUAL_COMPACT_PERIODIC_KEY_PREFIX	MANUAL_COMPACT_PERIODIC_PREFIX	manual_compact.periodic.
MANUAL_COMPACT_PERIODIC_TRIGGER_TIME_KEY	MANUAL_COMPACT_PERIODIC_TRIGGER_TIME	manual_compact.periodic.trigger_time
MANUAL_COMPACT_ONCE_KEY_PREFIX	MANUAL_COMPACT_ONCE_PREFIX	manual_compact.once.
MANUAL_COMPACT_ONCE_TRIGGER_TIME_KEY	MANUAL_COMPACT_ONCE_TRIGGER_TIME	manual_compact.once.trigger_time
MANUAL_COMPACT_TARGET_LEVEL_KEY	MANUAL_COMPACT_TARGET_LEVEL	target_level
MANUAL_COMPACT_BOTTOMMOST_LEVEL_COMPACTION_KEY	MANUAL_COMPACT_BOTTOMMOST_LEVEL_COMPACTION	bottommost_level_compaction
ROCKDB_CHECKPOINT_RESERVE_MIN_COUNT	ROCKSDB_CHECKPOINT_RESERVE_MIN_COUNT	rocksdb.checkpoint.reserve_min_count
ROCKDB_CHECKPOINT_RESERVE_TIME_SECONDS	ROCKSDB_CHECKPOINT_RESERVE_TIME_SECONDS	rocksdb.checkpoint.reserve_time_seconds
ROCKSDB_ENV_SLOW_QUERY_THRESHOLD	SLOW_QUERY_THRESHOLD	replica.slow_query_threshold

• Move MANUAL_COMPACT_BOTTOMMOST_LEVEL_COMPACTION_FORCE and MANUAL_COMPACT_BOTTOMMOST_LEVEL_COMPACTION_SKIP to class pegasus_manual_compact_service
• Move PEGASUS_CLUSTER_SECTION_NAME to src/common/common.h
• Move ROCKSDB_ENV_USAGE_SCENARIO_NORMAL, ROCKSDB_ENV_USAGE_SCENARIO_PREFER_WRITE and ROCKSDB_ENV_USAGE_SCENARIO_BULK_LOAD to class meta_store, because they are only used there.
• Move SCAN_CONTEXT_ID_VALID_MIN, SCAN_CONTEXT_ID_COMPLETED and SCAN_CONTEXT_ID_NOT_EXIST to src/server/pegasus_scan_context.h and src/client_lib/pegasus_scanner_impl.cpp, where belongs to server and client separately.