Update several references to First Look Media in the code, to better
reflect the current status, where Freedom of the Press Foundation has
taken over the stewardship of the project.
Fixes#343
Use the full image tag (dangerzone.rocks/dangerzone:latest) when
building the image. Else, we risk creating a `share/image-id.txt` file
with multiple IDs in it, if we have another
`dangerzone.rocks/dangerzone` image (with a different tag) in our dev
environment.
Add an optional --distro argument to build-deb.py, to specify the Debian
version in the package name, which currently is "1". This option may
prove useful when publishing packages to freedomofpress/apt-tools-prod,
where packages from different distros with the same names but different
contents are not accepted.
Skip the creation of the `share/container.tar` file, since it's not used
anywhere. Instead, pipe our `docker/podman save` invocations to `gzip`
directly, which will compress the tarfile on the fly. This saves both
time and disk space.
Introduce a script for installing Podman in Ubuntu Focal, in
environments that may, or may not, have sudo installed.
Also, update our CircleCI configuration to use this script when
installing Podman.
