Move timed_event to event header + cleanup

since the timed_event structure is tightly coupled to the events.c
file, and timed events, we should keep that structure in that module,
so we don't need to include the entire systems data strctures just to
handle some events.

Also, start the cleanup of unused event types, since we don't want
event types at all quite soon, but just callbacks.

Signed-off-by: Max Sikstrom <msikstrom@op5.com>
Commands: Break at end of case statements

A switch with independent cases should have break at the end of the
case, since the code will fall through otherwise.

Signed-off-by: Max Sikstrom <msikstrom@op5.com>
Add simplified schedule new event function + refactor simple events

Since callback based events is much easier to maintain in the events.c,
we should use that method. Also, that would keep all logic related to
the event at the same place as the code requesting the event, keeping
the all code related to a particular functionality together.

This first step updates the restart and shutdown process commands to
use callback events.

Signed-off-by: Max Sikstrom <msikstrom@op5.com>