remove old static libsccp.a, libmtp.a, libxua.a

Those static libraries were not used or maintained a long time ago.

We have a much more complete implementation of SCCP and xUA in
libosmo-sigtran.  That has been the basis of osmo-stp, as well as in
osmo-sgsn.git, osmo-bsc.git, osmo-msc.git.

The only user of the old static libraries was osmo-bsc-sccplite from
openbsc.git, which is unsupported for many years.

Change-Id: I299a32a2f8f61477cf49c8126567fef2092d5407
---
M Makefile.am
M TODO-RELEASE
M configure.ac
M debian/control
D debian/libosmo-sccp-dev.install
M debian/libosmo-sigtran-dev.install
M include/osmocom/Makefile.am
D include/osmocom/mtp/Makefile.am
D include/osmocom/mtp/mtp_level3.h
D include/osmocom/mtp/mtp_pcap.h
M include/osmocom/sccp/Makefile.am
D include/osmocom/sccp/sccp.h
D libosmo-mtp.pc.in
D libosmo-sccp.pc.in
D libosmo-xua.pc.in
M src/Makefile.am
D src/mtp_pcap.c
D src/sccp.c
M tests/Makefile.am
D tests/mtp/Makefile.am
D tests/mtp/mtp_parse_test.c
D tests/mtp/mtp_parse_test.ok
D tests/sccp/Makefile.am
D tests/sccp/sccp_test.c
D tests/sccp/sccp_test.ok
M tests/testsuite.at
26 files changed, 8 insertions(+), 3,967 deletions(-)