Adding 'haveged' entropy daemon package and service

Adding a sabotage package for 'haveged' - http://www.issihosts.com/haveged/index.html

Version 1.8 was recently released, builds cleanly with musl with no extra hacking required. 

I find this package lightweight and useful for systems that otherwise wouldn't have much randomness.

Hopefully I've done this whole pull-request thing right. Please let me know if I haven't, or how I can do it better. Cheers.