control: Provide trigger JSON to signal trigger subscribing

An upcoming signal class trigger will have additional JSON configuration
details for subscribing to it. This removes the generally unused event
name passed to each type of signal and replaces it with the trigger's
JSON configuration where used, which will not be used until the upcoming
`member` type of signal.

Change-Id: I7f9be935ba32ea71d0529f27e8e1c9016f7cec1f
Signed-off-by: Matthew Barth <msbarth@us.ibm.com>
2 files changed