Place snippets imported by apache::site in <VirtualHost>.

Import partial apache configuration directives meant to configure a single
vhost within a <VirtualHost> container. The default scope for apache
directives is the "main" server config which is almost never the place that
configuration for a particular site should be placed.

Bug: 52756

Change-Id: I476384076adbea7fecf0846c7076181cea0b0fea