db_config.md: add and update ALTER SYSTEM parameters

Summary

• db_config.md: add ALTER SYSTEM parameters — picodata@0175aa7f (24.7.0-89)
• db_config.md: update auto_offline_timeout — picodata@355e1483 (24.7.0-19)
• db_config.md: add and update ALTER SYSTEM parameters — picodata@b8d68456 (24.6.0-202)
• db_config.md: proofread and edit
• db_config.md: fix sorting

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• Close #386 (closed)
• Cherry-pick to: none
• Staging: https://docs.binary.picodata.io/picodata/asabirov_add_alter_system_parameters/reference/db_config/