Create a best practice series for k6 browser

[ankur22]

What

We want to make writing k6 browser scripts simpler by creating a series of opinionated best practice docs on how best to work with k6 browser.

Why

Users currently feel that they are left in the dark in terms of best practices. It's generally up to them to read the docs and examples and the to build from there. The issue is that users are likely to be facing the same issues over and over again.