Separate monitoring and move to 60s interval

Removes the dependency of the monitoring subsystem from the node
keepalives, and runs them at a 60s interval to avoid excessive backups
if a plugin takes too long.

Adds its own logs and related items as required.

Finally adds a new required argument to the run() of plugins, the
coordinator state, which can be used by a plugin to determine actions
based on whether the node is a primary, secondary, or non-coordinator.

node-daemon/pvcnoded/Daemon.py

@@ -255,10 +255,10 @@ def entrypoint():
         except Exception:
             pass
 
-        # Clean up any monitoring plugins that have cleanup
+        # Shut down the monitoring system
         try:
-            logger.out("Performing monitoring plugin cleanup", state="s")
-            monitoring_instance.run_cleanups()
+            logger.out("Shutting down monitoring subsystem", state="s")
+            monitoring_instance.shutdown()
         except Exception:
             pass