Should link to "Reporting a performance problem" docs

This was reported by Alex Mayorga in #perf:

> ¡Hola y'all! I used to point folks to https://developer.mozilla.org/en-US/docs/Mozilla/Performance/Reporting_a_Performance_Problem quite a bit but it seems like is now gone for good. Do y'all know of a better place?
> https://profiler.firefox.com/docs/#/ does not elaborate on the exact steps to file a performance bug in Bugzilla.
> Perhaps the last copy of https://developer.mozilla.org/en-US/docs/Mozilla/Performance/Reporting_a_Performance_Problem should be added in there?

These docs have moved to https://firefox-source-docs.mozilla.org/performance/reporting_a_performance_problem.html but the new page seems hard to find.

It would be good to have a link to it in a more prominent place, both in the profiler docs and maybe even on the profiler homepage.

┆Issue is synchronized with this [Jira Task](https://mozilla-hub.atlassian.net/browse/FP-427)