remove apt-related pre-provisioning from lxd profiles in Metabox

This is an relic from the times when we wanted to improve container
provisioning speed, but now, when testing from source we provision
everything with a normal apt execution, so this can go away. Also this
list had a potential to quickly go stale.

metabox/metabox/lxd_profiles/checkbox.profile

@@ -7,32 +7,3 @@ config:
       - 'sed -i "s/; enable-shm = yes/enable-shm = no/g" /etc/pulse/client.conf'
       - "perl -i -p0e 's/(Unit.*?)\n\n/$1\nConditionVirtualization=!container\n\n/s' /lib/systemd/system/systemd-remount-fs.service"
       - 'echo export XAUTHORITY=/run/user/1000/gdm/Xauthority | tee --append /home/ubuntu/.profile'
-    apt:
-      sources:
-        stable_ppa:
-          source: "ppa:hardware-certification/public"
-    packages:
-      - alsa-base
-      - gir1.2-cheese-3.0
-      - gir1.2-gst-plugins-base-1.0
-      - gir1.2-gstreamer-1.0
-      - gstreamer1.0-plugins-good
-      - gstreamer1.0-pulseaudio
-      - jq
-      - libgstreamer1.0-0
-      - mesa-utils
-      - pulseaudio
-      - python3-jinja2
-      - python3-markupsafe
-      - python3-packaging
-      - python3-padme
-      - python3-pip
-      - python3-psutil
-      - python3-pyparsing
-      - python3-requests-oauthlib
-      - python3-tqdm
-      - python3-urwid
-      - python3-xlsxwriter
-      - virtualenv
-      - x11-apps
-      - xvfb