Add org.apertis.demo.Platform runtime

Apertis development repository branch is add in runtime recipe, and not
in suite recipe, using pre_apt_script to avoid conflicts between GPLv2 and
GPLv3 packages.

Signed-off-by: Frédéric Danis <frederic.danis@collabora.com>

runtimes/org.apertis.demo.yaml

+---
+id_prefix: org.apertis.demo
+
+add_packages_multiarch:
+  - libc6
+  - libstdc++6
+
+pre_apt_script: |
+  set -eux
+  sed -i 's/\(^deb.*\)/\1 development/g' /etc/apt/sources.list
+  apt-get -y -q update
+
+sdk:
+  add_packages:
+    - busybox-static
+    - ccache
+    - debhelper
+    - dpkg-dev
+    - fakeroot
+    - gdb
+    - libc6-dbg
+    - ltrace
+    - strace
+    - valgrind
+...

suites/v2021dev1.yaml

+---
+can_merge_usr: true
+has_automatic_dbgsym: true
+strip_source_version_suffix: bv20\d\d.*b\d+|b\w\d+
+sources:
+  - label: apertis-target
+    apt_uri: 'https://repositories.apertis.org/apertis/'
+    apt_components:
+      - target
+...