We should still display the `source` advice when not in Vagrant or a
Droplet, since that's an important hint for anyone using local
installation on Linux.
We move the "If you are using Vagrant..." text a bit after to
highlight things nicely for folks who are running tools outside
Vagrant.
Also tighten text to avoid line-wrapping on an 80 character console.
This directory contains scripts that are used in building, managing,
testing, and other forms of work in a Zulip development environment.
Note that tools that are also useful in production belong in
scripts/ or should be Django management commands.