Changes Un/SubscribeVehicleData requests behavior.

[dev-gh]

'appID' parameter had been removed from Un/Subscribe requests for HMI API.
Logic of requests had been changed: un/subscribe request is sent only if
there are no apps subscribed for required parameters.

Implements: APPLINK-13345

Requirements to SDL:

1. In case app_2 sends SubscribeVehicleData (param_1, param_2) to SDL AND SDL has successfully already subscribed param_1 and param_2 via SubscribeVehicleData to app_1 SDL must:
   1.1. must NOT send SubscribeVehicleData(param_1, param_2) to HMI.
   1.2. respond via SubscribeVehicleData (SUCCESS) to app_2
2. In case app_1 sends SubscribeVehicleData (param_1) to SDL AND SDL does not have this param_1 in list of stored successfully subscribing params SDL must:
   2.1. transfer SubscribeVehicleData(param_1) to HMI.
   2.2. respond corresponding results received from HMI to app_2:
   2.2.1. in case SDL receives SUCCESS for param_1 SDL must store this param in list AND respond SubscribeVehicleData (SUCCESS) to app_2
   2.2.2. in case SDL receives erroneous result for param_1 SDL must NOT store this param in list AND respond SubscribeVehicleData (Result Code, success:false) to app_2
3. In case app_2 sends SubscribeVehicleData (param_1, param_3) to SDL AND SDL already subscribes param_1 via SubscribeVehicleData to app_1 SDL must send SubscribeVehicleData ONLY with param_3 to HMI.
4. In case SDL successfully subscribes param_1 for app_1 and app_2 via SubscribeVehicleData AND app_1 sends UnsubscribeVehicleData (param_1) SDL must:
   4.1. respond via UnsubscribeVehicleData(SUCCESS) to app_1
   4.2. stop sending OnVehicleData (param_1) ONLY to app_1
   (meaning: does not send UnsubscribeVehicleData(param_1) to HMI while there are others app still subscribed on param_1)

HMI_API changes:

1. param must be removed from SubscribeVehicleData

<function name="SubscribeVehicleData" messagetype="request">
<description>
Subscribes for specific published data items.
The data will be only sent if it has changed.
The application will be notified by the onVehicleData notification whenever new data is available.
To unsubscribe the notifications, use unsubscribe with the same subscriptionType.
</description>
<param name="appID" type="Integer" mandatory="true">
<description>ID of application that requested this RPC.</description>
</param>
<param name="gps" type="Boolean" mandatory="false">
<description>See GPSData</description>
</param>
<param name="speed" type="Boolean" mandatory="false">
<description>The vehicle speed in kilometers per hour</description>
</param>

1. param must be removed from UnsubscribeVehicleData

   This function is used to unsubscribe the notifications from the subscribeVehicleData function. ID of application that requested this RPC. See GPSData The vehicle speed in kilometers per hour

[AGaliuzov]

Andrey, could you please rebase this pull reques as it could not be merged

[dev-gh]

Done.