Add digital/analog sensor types & sonar cm msgs

[ArendJan]

Adds more digital/analog sensor types:

• "raw_data", "intensity", "line", "object"
• All same config layout:

     device:
      type: string
      default_value: mirte
      description: "Device to which the sensor is connected"
    pins:
      digital:
        type: string
        default_value: "-1"
        description: "Pin number for the sensor"
      analog:
        type: string
        default_value: "-1"
        description: "Analog pin number for the sensor"
    connector:
      type: string
      default_value: NONE
      description: "Connector to which the sensor is connected"
    frame_id:
      type: string
      default_value: ""
      description: "Frame ID for the sensor data"

Also adds distance unit option:

      unit:
        type: string
        default_value: m
        description: "Unit for the sonar distance data (m, cm)"
        validation:
          one_of<>: [ ["m", "cm"] ]

Distance is multiplied by 100 when set to cm. Not official ROS unit, but nice for web-interface users.