Changes - #365 - Jenkins

Install ca-certificates before Osmocom repo

Prepare for using https://downloads.osmocom.org/packages/ instead of
http://download.opensuse.org to download packages. Install
ca-certificates before attempting to use the repository, otherwise it
will print a warning and not use the repository and e.g. install
eclipse-titan from debian's repository instead of our repo.

Fix for:
W: https://downloads.osmocom.org/packages/osmocom:/latest/Debian_11/./InRelease: No system certificates available. Try installing ca-certificates.

Related: OS#5557
Change-Id: Icb6764601671b6e66591f33ede6d0f822811545a

debian-jessie-osmocom/Dockerfile debian-bullseye-build/Dockerfile debian-bullseye-titan/Dockerfile debian-buster-jenkins/Dockerfile debian-stretch-build/Dockerfile debian-stretch-jenkins/Dockerfile debian-bullseye-obs-latest/Dockerfile debian-stretch-obs-latest/Dockerfile osmo-ran/split/ran-trx-ipc/Dockerfile debian-sid-jenkins/Dockerfile osmo-ran/split/ran-bts_pcu/Dockerfile osmo-ran/split/ran-trx-uhd/Dockerfile osmo-ran/Dockerfile debian-bullseye-erlang/Dockerfile debian-buster-build/Dockerfile osmo-ran/split/ran-bsc_mgw/Dockerfile

Oliver Smith at 2:47 PM 6/27/22