frontend: Add azcore event logging, disabled by default

[mbarnes]

What this PR does

Debugging feature for logging azcore events.

Enable by setting AZURE_SDK_GO_LOGGING to "all" in the frontend-config ConfigMap ("all" is the only valid value at present, which logs events for all azure-sdk-for-go clients).

Jira: Added this while working on ARO-9674 - Frontend needs to run with at least two replicas
Link to demo recording:

Special notes for your reviewer

[mbarnes]

Closed because the AZURE_SDK_GO_LOGGING environment variable doesn't behave the way the documentation implies. Setting it to "all" enables the default log-to-stderr behavior, but calling SetListener also enables logging regardless of the environment variable, which I wasn't expecting.