Reproducible performance tests for OTLP logging

[a-thaler]

Description
Have a reproducible perf test setup as already in place with all other pipelines, assuring that there is no performance degradation as part of the log push (gateway) or file tail (agent) scenario when updating the otel-collector image

Criterias:

• Enrich the "otel-collector" image category with two new categories
• Test the pure log gateway perforance on base of telemetrygen, with the typical scnearios
• Test the agent scenario using log generators with stdout, similar to the metric agent setup