Add Missing SLO Property to Benchmark Objects

Adds:

  slos:
    - name: "lag trend"
      sloType: "lag trend"
      prometheusUrl: "http://prometheus-operated:9090"
      offset: 0
      properties:
        threshold: 2000
        externalSloUrl: "http://localhost:80/evaluate-slope"
        warmup: 60 # in seconds

to all benchmark objects defined in theodolite-benchmarks/definitions

Examples in theodolite/examples for the operator are already adapted.

Examples for standalone are left as they are.