Docker updates for NC 32

[mahiarirani]

This pull request updates the Nextcloud and Postgres service versions in both docker-compose.yml and docker-compose.stage.yml to ensure the stack uses the latest supported images. Additionally, it simplifies the service dependency configuration in the staging compose file.

Service version upgrades:

• Updated the nextcloud and cron service images to use Nextcloud version 32 instead of 31 in both docker-compose.yml and docker-compose.stage.yml [1] [2] [3] [4].
• Upgraded the postgres service to use the postgres:18-alpine image instead of postgres:alpine in both compose files [1] [2].

Configuration simplification:

• Removed the health check dependency on the proxy service in the depends_on section for the staging compose file, streamlining service startup.

[JoaoSRaposo]

Test:

• Changed the dev code this to this PR
• Removed NC_VERSION var from .env´
• Spined up the environment
  Result:
• Working fine in NC32