Improve documentation for setup process

[scottgonzalez]

The following steps/notes should be added:

• database setup
  • create database
  • create user
  • grant privs
• NameVirtualHost *:80 to enable vhosts
• use httpd-vhosts.conf if using Apache
• ensure all required extensions are enabled
  • mod_rewrite
  • vhost alias
  • anything else?
  • does this include PHP stuff? I remember @ryanneufeld had to make sure a couple PHP modules were active for the stripe integration on jquery.org to work without error.

[rdworth]

cc @ryanneufeld

[scottgonzalez]

I think I've covered everything now that I walked through this with @jenstrickland. If there's anything else, we can open issues for specific problems.