In #134418 we added support to list/enable/disable `SystemRuntime` and
`InstrumentationRuntime` plugins. We limited it to those two plugin
types to flesh out the idea with a smaller change.
This PR adds support for the remaining plugin types. We now support all
the plugins that can be registered directly with the plugin manager.
Plugins that are added by loading shared objects are still not
supported.
c677a11c8d