Apache config order

If you set an domain like 000abc.com the domain has a higher priority
than apaches 00_master.conf. Because of that the server default page
will be the domain 000abc.com instead of the imscp control panel.

This patch will change the apache config names from ``domain.conf`` to ``10_domain.conf``. So the order should be correct again.

**Atm I had no test server, so I couldn't test the changes.**