Add media explorer from Github

Fixes #61
Mirror pre-commit script

Fixes #25
Special VIP Scanner config for Quickstart

In VIP Quickstart, we want to default the VIP Scanner to
a VIP Theme Review check.

When we turn on theme submissions from the VIP Scanner,
we'll want to send them to the VIP Support address.

See: https://github.com/Automattic/vip-scanner/pull/68
Check if Quickstart is installed in vip-init