After the service split, some of the configuration, parsing and
validation was kept in the neutron core; ultimately this needs to
get closer to the services where it belongs.
This patch starts from ProviderConfiguration and ServiceTypeManager
classes, and aims at removing the hard-coded elements, like the list
of known advanced services, so that in the long run we can make
Neutron easier to plug with external services.
Partial-bug: #1473110
Depends-on: I44edcceba37ac58efcc0a53c9d1f835d9530344a
Depends-on: I8924234aadf786801ffc100d7daa27acc145a195
Change-Id: Ia4cad678e6c722ca05821dbdbf05d61523246a86
61121c5f2a