Write Vanilla Forums Local Development Setup Guide

[charrondev]

Currently our installations docs link out to the main projects README, which is a short guide only really only applicable to people installing a proper release version.

We should improve these docs, for Vanilla Developers, VIP cloud customers wanting to develop locally, and the open source community.

• Setup local PHP + Composer (and guide for setting up paths/.profile).

Note: Line to write a path value into the profile

echo 'export PATH=/some/path/here:$PATH' >>~/.profile

• Setup the docker container + vanilla release version
• How to install plugins and themes
• Cloud Customers - What to do if missing cloud addons.

Some common local development tips might be helpful as well

• Clearing memcache
• Clearing/disabling browser cache
• /utility/update
• Debug mode