doc/mesh-api: Forward compatibility modifications

doc/mesh-api: Forward compatibility modifications

The following methods are modified to allow for future development:

Interface org.bluez.mesh.Management1:

Old: void UnprovisionedScan(uint16 seconds)
New: void UnprovisionedScan(dict options)

    The options parameter is a dictionary with the following keys defined:
    uint16 Seconds
                Specifies number of seconds for scanning to be active.
                If set to 0 or if this key is not present, then the
                scanning will continue until UnprovisionedScanCancel()
                or AddNode() methods are called.
    other keys TBD

Old: void AddNode(array{byte}[16] uuid)
New: void AddNode(array{byte}[16] uuid, dict options)

    The options parameter is currently an empty dictionary

Interface org.bluez.mesh.Provisioner1

Old: void ScanResult(int16 rssi, array{byte} data)
New: void ScanResult(int16 rssi, array{byte} data, dict options)

    The options parameter is currently an empty dictionary

Change-Id: I6e9922a4f0ade412980693e463f024d363899530
Signed-off-by: Anupam Roy <anupam.r@samsung.com>