We already pushed dnsmasq part, that serves radio units into enb in 9f2b9db5.
However we need to push those bits further to ru/ for the following reasons:

- DHCP server is used to provide Radio Units with IP address only.
- without IP address assigned those RUs cannot be initialized and do not go to radio at all.
- in general we will need to initialize and setup radio units not only in eNB -
  for example UEsim will use the same code library to initialize radio units.
  Thus the proper place to keep everything required for RU to be operational have to
  be located inside ru/ and activated by that radio-units library.

/cc @jhuge, @xavier_thompson, @Daetalus
/reviewed-by @lu.xu
/reviewed-on !1479