Add benchmark action for skywalking

[Marcel-Ha]

Adds the benchmark action for skywalking. Its an adapted version of the scouter benchmark action.

[DaGeRe]

Thanks for the PR, was there a reason to set NUM_OF_LOOPS to 3 instead of 10 (how it is configured for the other benchmarks)?

[Marcel-Ha]

It is set to 3 in benchmarkScouterJava.yaml. You said I should base it on that, so I thought that was intentionally reduced to 3.

Should I increase it to 10 in both benchmarks?

[DaGeRe]

Sorry, my bad. The execution frequency, set by the cron configuration, should be lower in all Scouter, Skywalking, Elastic, etc.. We still need NUM_OF_LOOPS=10 for reliable results, would be nice if you could adapt this.

[Marcel-Ha]

Done.

[DaGeRe]

Thanks, look good