env/corellium: add README.md pointing to the Corellium dashboard
env/corellium: add README.md pointing to the Corellium dashboard

Add Zenly contact as well.

Change-Id: Id4cb32c010caad8a3ec0f7124196db06e95f900c
Reviewed-on: https://go-review.googlesource.com/c/build/+/249358
Run-TryBot: Elias Naur <1d6e1cf70ec6f9ab28d3ea4b27a49a77654d370e@eliasnaur.com>
Reviewed-by: Dmitri Shuralyov <d181b7fea0ec87c86ba5a890ab716db52498e3ba@golang.org>

golang/build,golang/build,golang/build,golang/build