Update DL1r-instructions.md to fix documentation

For mkdocs all hyperlinks have to be relative w.r.t. the docs directory.

Since making all hyperlinks relative to the docs directory would mess up the gitlab structure of hyperlinks, a way around is to make all hyperlinks to python or config files in the documentation point to the master branch of gitlab as absolute links.

Sorry, I don't have a better solution right now.

Closes #19 (closed)