Create new document on "Using memory wisely" and best practice for memory usage

[parlough]

This doc was planned to be placed at /perf/memory and linked to from Performance overview page, but it was never completed.

It's a good time to explore adding this page, especially as the memory tooling in DevTools and the upcoming leak_treaker have been improving a lot recently.

[rishitc]

Can you share any recommended references, such as conference talks, blogs, videos, etc., to review before working on this doc, if any?

I can review them and try writing up this document.