Use the create action instead of modify

Using the modify action for the user resource doesn't create the user if it doesn't exist.

The create action creates the user as well as modifies it if it exists.
Move configuration of the web server until after installing nagios

Configuring the web server first causes an error because the document root doesn't exist at the time apache is trying to start (because we haven't compiled/installed nagios yet)
Split up creating the nagios group and adding the web user

Create the nagios group when creating the user, and then add the web server (apache/nginx) user to the group after the web server is created at the bottom.
previous patches