Refine start-up performance logs

[cdamus]

Feature Description:

An earlier contribution, PR #10116, added log messages with timings of frontend application loading, especially as it pertains to initialization of plugins. It would be nice to do similarly in the backend, to add log messages showing the timing of start-up tasks on that end that are subject to potential performance problems. As much as possible, the look-and-feel of the timing log API and messages on the frontend and backend should be aligned, preferably a single API that has different implementations on each end if appropriate.