Implement `connections_count` metric
The connections_count
is an OTEL counter that represents the number of
currently open connections from all agentks to KAS. This counter uses an
underlying redistool.ExpiringHash
that maps a single static key to
connection ids. This hash works in the exact same way as the already
existing connected_agents
hash.
Closes Improve instrumentation around connected agents (#523 - closed)
Edited by Timo Furrer