Classic drivers will be deprecated, add hardware types for
staging drivers. "staging-" prefix used for entrypoints.
The DevStack plugin is amended to enable all hardware types and
interfaces registered by the ironic-staging-driver package
to test that they do not break ironic-conductor start when enabled
For this a new script is added to read entrypoints registered by a Python
package.
As previousely, by default `iboot` drivers are not enabled
as they require a client library not available on PyPI.
Change-Id: I26541adc9b99f7a436be0e3f8ef31c0ff64ff5d4