Blueprint quantum-service-type
This patch allows for managing service types through the API.
The default service type is specified in the configuration file.
The patch also provides a 'dummy' API extension, which uses the
'dummy' service plugin, as a PoC for usage of service type.
The dummy API extension is used in unit tests only.
Change-Id: I97d400b941fa7925b0efa0fd0d35c07419ff6bfa