Add Brave browser to browsehappy.com

[tellyworth]

In the same style as the others.

[macmanx]

Hmmm, I have misgivings about a browser that is practically built around crypto mining.

Is there any particular reason for including a browser that's not The Big 5?

If there's a need for yet-another Chromium browser besides Chrome, Edge, and Opera, what about ​https://vivaldi.com/ instead which offers the same un-Googled Chromium with a focus on privacy and no crypto mining?

[tellyworth]

I understand @matt asked for Brave to be included.

[renyot]

PR: ​https://github.com/WordPress/browsehappy/pull/64 (Screencast included)

[coffee2code]

In 12487:

Browse Happy: Add Brave browser.

Props renyot.
Fixes #6845.