[#1838] Self contained repository.


Problem description
===================

This add support for having independent repository, ie they will no longer depend on brink repo.


Changes description
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instead of using brink/cache the cached files will be downloaded in REPO/cache folder.

I first tried to put them in REPO/build-*/cache ... but then the cache would be removed at each clean operation and a huge new download will be required.

With this change you should be able to place the repository in any folder structure.


How to try and test the changes
===============================

reviewers @alibotean @dumol 

Check that changes make sense.

Thanks!