generate the interface class and run the getter and setter services
Example of call: interface_factory('laser_descriptor',
'lama_interface/get_laser_descriptor',
'lama_interface/set_laser_descriptor').
Parameters
----------
- interface_name: str, uniquely identifies an interface between jockeys
and the database.
- getter_srv_msg: str, identifies the service message used when retrieving
a descriptor from the database. For example
'lama_interfaces/GetVectorLaserScan'.
Service definition must be in form:
int32 id
---
* descriptor
- setter_srv_msg: str, identifies the service message used when adding
a descriptor to the database. For example
'lama_interfaces/SetVectorLaserScan'.
Service definition must be in form:
* descriptor
---
int32 id
This function should be called only once with each parameter set because
it starts ROS services and an error is raised if services are started
twice.