add proxying with client certificate test

typo

add a test for the `proxy relay-to' rule

rename variable

run all kinds of tests via tests.sh/runtime while there also change the dependency in the makefile: iri_test should be alone, not as deps of `data'.

re-add sha script; it's used in the Makefile While there, use it in the tests too

rework the regression suite The tests are still there, the suite is equivalent to the old one, but this one is better structured. The biggest annoyance I had with the old one was that it wasn't straightforward to test only a specific set of tests. It's still impossible, but it's way easier to do it now. This extract all the tests to their own functions. It's overall better in all possible regards.