feat: implement repmgr

• feat: add shell configuration
• chore: reorder init scripts
• feat: add repmgr
• fix: psql_hba-security
• fix: remove iptables dependency
• fix: repmgr_hba_security
• fix: add silent option to database ready check
• chore: code format
• fix: repmgr commands
• fix: dependency on iptables
• fix: load environment for shell
• chore: add example directory for psql-3
• fix: add param for is_db_ready func
• fix: return value of func
• fix: remove obsolete code
• fix: move repmgr configuration
• fix: remove default repmgr.conf
• fix: add s6 service signal
• fix: service commands
• fix: configure repmgr directory
• fix: file permissions
• chore: code format
• fix: default archive command
• fix: enable archive when repmgr is enabled
• fix: permissions
• fix: witness server
• fix: permissions
• chore: update values of docker-compose
• fix: set example remgr/psql-2 as witness
• docs: update docs
• docs: update
• chore: update project settings
• chore: rename services
• chore: reorganize functions
• fix: set local vars readonly
• feat: add func env_set
• chore: reorganize functions
• chore: code format
• chore: add comments to functions
• chore: fix comment
• chore: update comments
• feat: add env_del
• fix: env_set
• chore: update comments
• chore: code format
• chore: update project settings
• chore: add mermaid diagram support to project
• docs: update
• docs: update
• fix: rename function
• chore: update comments
• fix: service dependencies
• fix: repmgr override
• fix: wal commit
• fix: repmgr
• fix: file permissions
• fix: func reference
• fix: load environment vars
• fix: load functions
• fix: service dependency
• fix: archive
• fix: repmgr hba
• fix: conditionally enable repmgr service
• chore: add logging
• fix: mask REPMGR_PASS in loggin
• chore: fix base GID
• fix: remove archive volume
• fix: add psql-4 to repmgr example
• fix: bashrc link
• fix: update shell environment and aliases
• fix: update repmgr
• fix: psql commands
• fix: shell aliases
• fix: repmgr control commands
• feat: add repmgr-node-rejoin command
• fix: primary to standby failover
• fix: psql_is_initialized
• chore: add clean-examples
• fix: replication mode
• chore: add node id to repmgr example
• chore: fix make clean-*
• fix: repmgr-standby
• fix: node_id
• fix: repmgr-config
• fix: REPMGR_NODE_ID provisioning
• docs: update