games/pyspacewar: Update to 1.2.0

Remove DOCS option, the installed files are small.
Switch to PYPI.
Switch to DISTVERSION.
Update WWW entries.
Switch to manual pkg-plist.
Use desktop file provided by upstream.
Install an icon to pixmaps directory to show it's icon in
application launchers.
Pet port{fmt,lint,clippy}.
Submitter becomes maintainer.

Changelog: https://github.com/mgedmin/pyspacewar/blob/master/NEWS.rst

PR: 284023