Update software on guacamole server

[craddm]

✅ Checklist

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⤴️ Summary

Updates the versions of Guacamole, nginx, and Postgres used on the Guacamole remote desktop server.

In addition, sometimes the Postgres database did not finish initializing before Docker launched Guacamole, and thus Guacamole sometimes did not function. This PR adds a health check to the docker-compose.yaml to make Docker wait until the Postgres database is fully responsive. This necessitated migrating from Docker Compose v1 - docker-compose - to Docker Compose v2 - docker compose. Compose v1 is no longer supported, and the necessary syntax to perform the health check was not supported.

🌂 Related issues

Relates to #1738 but does not close it, as this PR only focuses on the Guacamole server.

🔬 Tests

Deployed a Guacamole server within an SRE and checked that it functioned correctly.