Created basic template for dhcpd.conf

Hi there,

I've turned ``dhcpd.conf`` into a jinja-template complete enough to generate something functionally identical to the sample-configuration.
I've also filled pillar.example with the configuration-data from the sample-configuration so one can use pillar.example as a working base for one's own ``pillar['dhcpd']``.
For now I've only tested trying to generate the sample-configuration but it should work for many simple use-cases.

Regards, Florian