Because:

- ssh server is needed for and used by ru/lopcomm/ only
- 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 @lu.xu, @tomo, @xavier_thompson, @Daetalus
/reviewed-by @jhuge
/reviewed-on nexedi/slapos!1510