* Split tracing component code into modules.
* Repatriate Tracing and simplify config handling.
We upstreamed our Tracing component, expecting not to have to exert fine
control over the tracing settings. But this turned out not to be the case, and
now that we want to do other things (flamegraphs, journalctl, opentelemetry,
etc), we end up with really awkward code (as in the current flamegraph
handling).
This also makes use of the changes to `init()` to load the config early to pass
configuration data into the components, which avoids the need for the
refactoring in #775.
Finally, we restore support for the `-v` flag when the filter is unset. Closes#831.
* Disable tracing and metrics endpoints by default.
Closes#660.
* Switch back to upstream Abscissa.
* Integrate flamegraph support into the new Tracing component.
* Pass -v in acceptance tests to get info-level output.
* Clean up acceptance test code.
Jane Lusby
Alfredo Garcia
Henry de Valence