Move packages to gz and add ignition alias

[chapulina]

• Part of Debian packages from ignition to gz gazebo-tooling/release-tools#736
• Alternative to Migration to gz- packages #12

After ff68c6c

[chapulina]

Working

The following additional packages will be installed:
  libavdevice-dev libavfilter-dev libignition-common5 libignition-common5-core-dev libignition-common5-events
  libignition-common5-events-dev libignition-common5-geospatial libignition-common5-geospatial-dev libignition-common5-graphics
  libignition-common5-graphics-dev
The following NEW packages will be installed:
  libavdevice-dev libavfilter-dev libgz-common5 libgz-common5-av libgz-common5-av-dev libgz-common5-core-dev libgz-common5-dev
  libgz-common5-events libgz-common5-events-dev libgz-common5-geospatial libgz-common5-geospatial-dev libgz-common5-graphics
  libgz-common5-graphics-dev libgz-common5-profiler libgz-common5-profiler-dev libgz-common5-testing libgz-common5-testing-dev
The following packages will be upgraded:
  libignition-common5 libignition-common5-core-dev libignition-common5-events libignition-common5-events-dev
  libignition-common5-geospatial libignition-common5-geospatial-dev libignition-common5-graphics libignition-common5-graphics-dev