Feature: CICS tracing

[deejgregor]

What Does This Do

Adds tracing for CICS calls made to an IBM CICS Transaction Gateway (CTG).

Motivation

Outbound client calls to CICS functions are valuable to be traced similar to outbound REST calls or other RPC calls. This adds basic tracing (but not context propagation) to these calls, in addition to setting a peer.hostname to allow the downstream CICS Transaction Gateway (CTG) host to be shown as an inferred service.

Additional Notes

Methods instrumented

ECIInteraction.execute

Instruments the entry point for CICS
calls via IBM's javax.resource.cci.Interaction implementation,
creating cics.execute span and recording a few tags.

A few tags from the
OTEL RPC semantic conventions
are added, as well.

JavaGatewayInstrumentation.flow

Records the peer.* tags on
the cics.execute span created above, or if it doesn't exist,
creates a new gateway.flow span.

Once a connection is made, some the peer and local IP address and port are recorded.
Datadog does not normally record the the local side of
network connection details, but this was added to assist with debugging network issues and as an example of how to add this data.

Other notes

The tests don't fully exercise the CICS client-side code, however
they exercise enough to ensure the instrumentation creates spans
and adds tags as expected.

This requires a few JAR files from IBM's CICS SDK for compliation
and testing that are not available in Maven Central. A tar.gz
artifact is downloaded from IBM's public CICS support archive
and the necessary JARs are extracted, following the same pattern
used for the JBoss Wildfly smoke tests.

Contributor Checklist

• Format the title according the contribution guidelines
• Assign the type: and (comp: or inst:) labels in addition to any useful labels
• Don't use close, fix or any linking keywords when referencing an issue.
  Use solves instead, and assign the PR milestone to the issue
• Update the CODEOWNERS file on source file addition, move, or deletion
• Update the public documentation in case of new configuration flag or behavior

Jira ticket: [PROJ-IDENT]