With Cluster::Node$metrics_port being optional, there's not really
a need for the extra script. New rule, if a metrics_port is set, the
node will attempt to listen on it.
Users can still redef Telemetry::metrics_port *after*
base/frameworks/telemetry was loaded to change the port defined
in cluster-layout.zeek.
After the introduction of @if ... analyze, a lot of warnings were
triggered due to nested @if and @if .. analyze usage.
Add a test for coverage of all policy scripts in cluster mode
for the usual node types so this does not happen again.
