Add ADMIN_PASSWORD env variable

# Motivations
Being able to configure the admin password would be quite helpful

# Modifications
- Add `ADMIN_PASSWORD` to the list of environment variables, which adds `--adminpassword` to the server arguments

docker-compose.yml

@@ -15,5 +15,6 @@ services:
          # Enable the environment variables below if you have COMMUNITY=true
          # - SERVER_PASSWORD="worldofpals"
          # - SERVER_NAME="World of Pals"
+         # - ADMIN_PASSWORD="someAdminPassword"
       volumes:
          - ./palworld:/palworld/