doc/mesh-api: Add "options" dictionary to Send/Publish

doc/mesh-api: Add "options" dictionary to Send/Publish

This modifies Send, DevKeySend and Publish methods
on mesh.Node interface to include additional argument "options".
This new argument is a dictionary that currently has only one
new key word defined for Send() and DevKeySend():
    "ForceSegmented" - to force small payloads to be sent as
    		      one-segment messages

In case of Publish(), and additional keyword is defined
     "Vendor" -  16-bit Company ID as defined by the Bluetooth SIG

Other key words may be defined in future to accommodate evolving
requirements of Mesh Profile specification.

Also, the addition of "options" dictionary to Publish allows to
eliminate VendorPublish() method (taken care by "Vendor" keyword).

Change-Id: I5fa1ed0e03875cc4c16723aa6005b38fcf031255
Signed-off-by: anuj.bhumiya <anuj.bhumiya@samsung.com>