Added wiki page about Repositories

[Rui Tiago Matos]

Hi,

I've just added a little bit of wisdom to the wiki regarding
repositories[1]. I've had far too many GNU/Linux newbies asking me for
how to install software :)

I linked to it from [2] and [3]. Yet I don't like the location of [3].
Please someone more knowledgeable about the wiki structure move it to
a more appropriate place or drop me a mail about it. I also think it
could be added to a FAQ somewhere.

Rui

[1] https://www.ubuntulinux.org/wiki/Repositories
[2] https://www.ubuntulinux.org/wiki/AddingRepositoriesHowto
[3] https://www.ubuntulinux.org/wiki/DocumentationArea