Changes to Create REST API session

added the new optional request property attachNotificationHandler

request body became optional

added the non-success response with the status 400

added the optional property description to the response with the 401 status

added the optional property error to the response with the 401 status

added the optional property session to the response with the 200 status

added the optional property sessionHandle to the response with the 200 status

api operation id createSession was added

added the non-success response with the status 401

request body became required

the optional response header Session-Id removed for the status 200

removed the request property attachNotificationHandler

removed the optional property session from the response with the 200 status

removed the optional property sessionHandle from the response with the 200 status

api operation id createSession removed and replaced with

removed the non-success response with the status 400

removed the non-success response with the status 401