Allow specifying the encoder metadata

[bruno-f-cruz]

https://github.com/AllenNeuralDynamics/aind-data-schema/blob/773ee35126cb91689a0254d9d561b55f04093233/src/aind_data_schema/device.py#L575

On top of the treadmill settings, it would be helpful to also specify information regarding the encoder being used. For instance:

      "pulsesPerRevolution": {
        "default": 2880,
        "type": "number"
      },
      "invertDirection": {
        "default": false,
        "type": "boolean"
      }

Is this already contemplated elsewhere? I looked for Encoder and did not find it.