Add the command list-repos to jw-projects.py. It is meant to do the
same thing as "git-srv-adm.sh list-personal-projects", i.e. enumerate
remote Git repositories, but also support additional servers and
protocols. As of this commit, support for https://github.com and for
forgejo installations over HTTPS is implemented.
Signed-off-by: Jan Lindemann <jan@janware.com>