TA Roadmap: repo-strategy

[nhaagen]

I was asked to expand on the idea of repo-pattern in T&A and how this might be a strategy as well. This is what I came up with so far; happily expecting comments ;)

(some of the mentioned thing I started out with in https://github.com/nhaagen/ILIAS/tree/_trunk/TA/repo , but that if far from ready/definite)