CLI environment variables

These environment variables affect the serverpod command:

• SERVERPOD_HOME points to the Serverpod framework directory. It is only required when running the CLI in development mode, from a checkout of the Serverpod repository. A normal installation does not need it.
• Server configuration variables, the SERVERPOD_* and SERVERPOD_PASSWORD_* variables, apply to commands that load your project's config, such as serverpod start and serverpod database. See the Configuration reference.