This eliminates one place in which we currently need to mirror changes to the
script-land Cluster::Node record. Instead of keeping an exact in-core equivalent, the
Supervisor now treats the data structure as opaque, and stores the whole cluster
table as a JSON string.
We may replace the script-layer Supervisor::ClusterEndpoint in the future, using
Cluster::Node directly. But that's a more invasive change that will affect how
people invoke Supervisor::create() and similars.
Relying on JSON for serialization has the side-effect of removing the
Supervisor's earlier quirk of using 0/tcp, not 0/unknown, to indicate unused
ports in the Supervisor::ClusterEndpoint record.
Currently this requires using this with a normal cluster - or sending
messages by yourself.
It, in principle, should also work with SQLITE - but that is a bit
nonsensical without being able to change the storage location.
More aspects of the cluster configuration to get fleshed out later,
but a basic cluster like one would use for a live deployment
can now be instantiated and run under supervision. The new
clusterized-pcap-processing supervisor mode is also not done yet.
For backward compatibility when reading values, we first check
the ZEEK-prefixed value, and if not set, then check the corresponding
BRO-prefixed value.
* All "Broxygen" usages have been replaced in
code, documentation, filenames, etc.
* Sphinx roles/directives like ":bro:see" are now ":zeek:see"
* The "--broxygen" command-line option is now "--zeexygen"
