refactor: move out some parameters from _pico_db_config to config file

Summary

• feat: move out some parameters from _pico_db_config to config file

• auto_offline_timeout
• max_heartbeat_period
• snapshot_read_view_close_timeout
• governor_raft_op_timeout
• governor_common_rpc_timeout
• governor_plugin_rpc_timeout

• feat: move out some parameters from config file to _pico_db_config

• checkpoint_interval
• checkpoint_count
• max_concurrent_messages

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• Close #1171, #1222
• Cherry-pick to: none
• Docs follow-up: docs#421, docs#426
• Changelog is updated