there is no open5gs_enb so having the epc in the name is redundent, also
it safes typing and allows longer scenario configs without exceeding
filename limit.
Change-Id: Ib10bc6031ecc8de88a9c718b136d2641ce46e11d
Despite open5gs allowing to change the GTP ports in the config file, in
reality changing those values to something else than the standard prot
will fail. Hence, we must use the standard port. As a result, we must
use different IP addresses in each process to avoid ip+port collisions.
Let's use some loopback addresses which shouldn't require extra
configuration on the host, and still only requiring 1 run_node as per
existing EPCs, with the limitation that only 1 open5gs EPC instance can
be run at one in a given run_node.
Related: https://github.com/open5gs/open5gs/issues/897
Change-Id: Id3062c6ad9d6de4c6066547e1e46edad5da285c1