Bugfix i17 s1ap ue capabilities



See merge request !39

download asn1c from oai gitlab

We need to test at least one attach by the UEs of the test setup, to check that the local asn1c is the same as the one from github we used so far.

I don't think we need to do lots of traffic, it's only about control plane (rrc, s1ap).

And of course see if compilation is still ok.

See merge request !40

the official asn1c repository at github posed problems to
some people in the past. It's better to have it locally
for such a critical piece of the software.