Mention `Apache Server Configs` in `humans.txt`

The Apache server configs have evolved into their own separate
project, and thus, they are now considered an external component.
Docs: Move `crossdomain.xml` info into `misc.md`

Update and improve the `crossdomain.xml` related documentation,
as well as move it into the `misc.md` file.

The move is made in order to be more consistent (we don't have
special pages for any of the other "miscellaneous" files).
Docs: Update and improve `faq.md`