RFR: 1482: Add more metrics

[Erik Joelsson]

In order to better analyze Skara bot performance, I need more metrics. Specifically the skara_runner_*_time gauges are pretty useless in their current form. They would be more useful as counters so we could look at the total execution time for workitems for a specific bot instead of randomly picked single executions of the same.

-------------

Commit messages:
 - Merge branch 'master' into SKARA-1482-metrics
 - Add counter versions of skara_runner gauge metrics

Changes: https://git.openjdk.org/skara/pull/1339/files
 Webrev: https://webrevs.openjdk.org/?repo=skara&pr=1339&range=00
  Issue: https://bugs.openjdk.org/browse/SKARA-1482
  Stats: 12 lines in 1 file changed: 9 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/skara/pull/1339.diff
  Fetch: git fetch https://git.openjdk.org/skara pull/1339/head:pull/1339

PR: https://git.openjdk.org/skara/pull/1339