Add package repo links to the download page

[pchote]

We have packages in the official repositories of more than one linux distro. The blurb for each of these platforms should be updated with the commands required for installation.

The blurb should include a notice that these are maintained by a third party and may be out of date (desura too) - see #18 for more discussion.

[Mailaender]

• http://www.playdeb.net/software/OpenRA
• http://software.opensuse.org/package/openra
• http://packages.gentoo.org/package/games-strategy/openra
• https://www.archlinux.org/packages/community/any/openra/

are the ones I found so far.

[Mailaender]

openSUSE and Ubuntu are one-click-install.

[Mailaender]

I recently introduced @cjshmyr to https://github.com/desura/Desurium/wiki/Notes-For-Publishing-On-Desura so this will continue when I am gone.

[Mailaender]

http://pkgs.org/download/openra revealed a package for Mageia and has installation instructions for all repositories. Maybe we should just link it?

[cerebrum]

Gentoo stable ebuilds are usually in the tree. But playtests are not and you should probably give this link for anybody wanna get playtests from my overlay easily:
http://www.sleipnirstuff.com/forum/viewtopic.php?f=82&t=14972

[Mailaender]

I think we also should handle http://openra.res0l.net/download/#desura as a repository that is shown on the per platform page instead because the whole "Which Build?" section makes no sense at all.

[Mailaender]

I finally did it now. See #131.