Incorporate use of new MWDI 'device-status-metadata' service for keeping list of connected/connecting devices

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• MWDI will in its upcoming release v1.2.0 offer a new service /v1/provide-device-status-metadata, which provides, among other data, the exact connection status for all mount-points known to the controller (e.g. 'connected', 'connecting',...).

• APTP shall make use of this service to perform a cyclic load of the the list of known mount points (with respective connection status) and store it internally

• The periodical call of this service (a callback of /v1/embed-yourself) shall replace the current calling of /v1/provide-list-of-connected-devices

• For the case that the requested device is found to be in 'connecting' state, new error code and message must be defined and added to the ApplicationPattern and to the APTP specification ( for it to be returned to APT).

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Possible defintion of Error Response:

'462':
  description: 'Response in case the mountName provided in the request is in "connecting" state in the list of known devices'
  content:
    application/json:
      schema:
        type: object
        required:
          - code
          - message
        properties:
          code:
            type: integer
            minimum: 462
            maximum: 462
            format: int32
          message:
            type: string
            enum:
              - 'Connecting. Connection to the requested device has been lost or interrupted'