Improve Port Validation for Node Configs

[linear]

in node/node.go try to externalize these validation to the config creation itself. i.e., move it upstream.

givenPortNumber := cfg.BacalhauConfig.API.Port
if givenPortNumber < minPortNumber {
    return nil, fmt.Errorf("invalid negative port number: %d", cfg.BacalhauConfig.API.Port)
}
if givenPortNumber > maxPortNumber {
    return nil, fmt.Errorf("port number %d exceeds maximum allowed value (65535)", cfg.BacalhauConfig.API.Port)
}

safePortNumber := uint16(givenPortNumber)

[linear]

ENG-293 Improve Port Validation for Node Configs