Unify Dashboard & Webhook events (#394)

This change unifies the previously adhoc SignalR events and Webhooks into a single event format.

src/api-service/__app__/timer_tasks/__init__.py

@@ -8,7 +8,7 @@ import logging
 import azure.functions as func
 from onefuzztypes.enums import JobState, TaskState
 
-from ..onefuzzlib.dashboard import get_event
+from ..onefuzzlib.events import get_events
 from ..onefuzzlib.jobs import Job
 from ..onefuzzlib.orm import process_state_updates
 from ..onefuzzlib.tasks.main import Task
@@ -38,6 +38,6 @@ def main(mytimer: func.TimerRequest, dashboard: func.Out[str]) -> None:  # noqa:
 
     schedule_tasks()
 
-    event = get_event()
-    if event:
-        dashboard.set(event)
+    events = get_events()
+    if events:
+        dashboard.set(events)