Added ethtool class for installing ethtool.

Closes #2.

We need to kinda decide what the "name" of this module is. Fixtures kinda implies it is "type-ethtool", but the Modulefile says `bobtfish/ethtool`. Can we just go with ethtool?

A possible TODO could be more OS support. I'm kinda assuming the package is called "ethtool" across the board. 

I'm not currently testing resource ordering. 

Also I like strict types. If you want me to change it to str2bool I would concede.