Add watchtower and config-watcher + move from client.txt to .env

[adnanhashmi09]

This pull request includes significant updates to the docker-compose.yml file and the environment configuration. The changes primarily focus on container management, environment variables, and service dependencies.

Updates to docker-compose.yml:

• Added container names for better identification and management (middleware-db, middleware-dbmate, middleware-sync-agent, middleware-watchtower, middleware-config-watcher). [1] [2] [3]
• Introduced a new watchtower service for automated container updates and Slack notifications.
• Added a config-watcher service to monitor configuration changes and trigger container restarts, with Slack notifications for status updates.
• Updated volumes and environment configurations to support the new services and functionalities.

Environment configuration:

• Renamed client.txt to .env and added new environment variables (ORG_NAME, SLACK_NOTIFICATION_HOOK).