Merge duplicate repo description in one that can be shared

The repository setup is the same for all three nodes - and needs
updates for every release. So, let's have it only once in a common
section and reference it from other places.

I've also fixed markup of the shared part.

Change-Id: I5d2b96744a1bcfa9cb11f60c8bae5bd0ee076ede
Merge "Merge duplicate repo description in one that can be shared"