Tweaked the openSUSE build service links

This adds links to the openSUSE wiki with further information
* https://en.opensuse.org/OpenRA
* https://en.opensuse.org/Games

and avoids linking the download page twice. Also it may be confusing that you don't get a package, but another HTML site with instructions. I tried to mitigate that by renaming the button a bit.
Yes, the user frontend is unfortunate. It does not differentiate between some user repositories which are just experiments or forks and official development projects such as games. That is why we avoid linking software.opensuse.org/package/openra here.