Migrate/address missing articles in new site

[pbakaus]

I couldn't find the right mapping for the following resources, they either don't exist (yet) in the new IA or I missed them:

Not moved:

/videos /tips-and-tricks (created a mapping, but we need to port these over) /extensions-gallery /contributing /clean-testing-environment Unsure:

/blackboxing /settings /rendering-settings /heap-profiling-summary /heap-profiling-dominators /heap-profiling-dom-leaks /heap-profiling-containment /heap-profiling-comparison /authoring-development-workflow

This is a tracking bug to make sure we've found new homes for all of the above and linked them properly.