Add continuous benchmarking

[tobiasdiez]

We have a jmh benchmark suit but this is never run and/or checked for performance regressions. Thus it would be good to have a continuous benchmarking solution.

Github action that goes in this direction (but has not yet support for jmh) https://github.com/marketplace/actions/continuous-benchmark https://github.com/bobheadxi/gobenchdata

[github-actions[bot]]

This issue has been inactive for half a year. Since JabRef is constantly evolving this issue may not be relevant any longer and it will be closed in two weeks if no further activity occurs.

As part of an effort to ensure that the JabRef team is focusing on important and valid issues, we would like to ask if you could update the issue if it still persists. This could be in the following form:

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