* proxy is set through build arguments.
settings stub for network, git , sudo has been removed.

* removed comments not parsed correctly by docker.

* changed: tumbleweed.docker proxy is set through build argument.

Co-authored-by: Nadeem <nadeem.shehzad@desy.de>

For some reason I thought that this is not available anymore

For now run in parallel with bionic; We can drop bionic if focal builds
reasonably well