Changes to Create a new session

removed the request property session_id

added the new optional request property id

the request property user became required

the project_id request property's minLength was increased from 0 to 36

added the pattern ^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$ to the request property project_id

the project_id request property's maxLength was set to 36

added the new optional request property session_id

the id response's property pattern ^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$ was added for the status 201