Print timestamp when uploading results to logstash

[msimberg]

This is a debugging PR (for now). Just trying to understand how long the submission takes typically.

[codacy-production]

Coverage summary from Codacy

See diff coverage on Codacy

Coverage variation	Diff coverage
✅ +0.10% (target: -1.00%)	✅ ∅ (target: 90.00%)

Coverage variation details

	Coverable lines	Covered lines	Coverage
Common ancestor commit (f182d67)	18212	13736	75.42%
Head commit (f31dd7e)	18212 (+0)	13754 (+18)	75.52% (+0.10%)

Coverage variation is the difference between the coverage for the head and common ancestor commits of the pull request branch: <coverage of head commit> - <coverage of common ancestor commit>

Diff coverage details

	Coverable lines	Covered lines	Diff coverage
Pull request (#1358)	0	0	∅ (not applicable)

Diff coverage is the percentage of lines that are covered by tests out of the coverable lines that the pull request added or modified: <covered lines added or modified>/<coverable lines added or modified> * 100%

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[msimberg]

Closing since #1359 adds timestamps. I've also seen enough: uploading results from the build stage takes ~15 minutes: https://gitlab.com/cscs-ci/ci-testing/webhook-ci/mirrors/479009878135925/5304355110917878/-/jobs/8503666641. That is far too long, so I'll open a separate PR to try improve that.