add links to windows and ubuntu-based gocd
make sample commands consistent between script/test and systemd

It doesn't matter if you start containers via systemd or scripts.
The sample commands should work via copy-paste in both cases.
simplify deployment instructions
add links to trusted builds on docker registry
add svn to base image so we can use subversion materials

resolves error:

    Failed to find 'svn' on your PATH. Please ensure 'svn'
    is executable by the Go Server and on the Go Agents where
    this material will be used.