Log a warning message if unrecognized EDGEDB_ envvars are set

[fmoor]

If a user miss spells an environment variable like EDGEDB_SERVER_USERNAME instead of EDGEDB_SERVER_USER it can be very difficult to figure out why they can't authenticate after the container is running.

Log a big noisy warning when unrecognized EDGEDB_* environment variables are detected to help users discover what went wrong.