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/util/keepalive.py

@@ -859,11 +859,6 @@ def node_keepalive(logger, config, zkhandler, this_node, monitoring_instance):
     except Exception:
         logger.out("Failed to set keepalive data", state="e")
 
-    # Run this here since monitoring plugins output directly
-    monitoring_instance.run_plugins()
-    # Allow the health value to update in the Node instance
-    time.sleep(0.1)
-
     if config["log_keepalives"]:
         if this_node.maintenance is True:
             maintenance_colour = logger.fmt_blue