Remove all external frameworks implementations

Kirk supports the execution of certain kselftests and liburing
testing suites. It was initially created as an experiment.

We have made attempts to implement these features, but it seems
we have not succeeded. They appear to be largely unused by most
users and are creating a bottleneck for new Kirk implementations,
such as the automatic installation of LTP inside the SUT.
This feature would be particularly beneficial for QEMU vanilla
images. We had it in the past already and probably it's time to
get this feature back. And we should probably implement it for
other testing suites due to the current API: something that we
really don't want to do (see eBPF kselftests compile madness).

Another concern is the maintainability of supporting for additional
testing suites. While they are interesting, the implementation is
somewhat flawed. Each testing suite has its own
input/output/configuration/compilation methods, leading to
confusion and over-engineered solutions. While we understand that
no solution is perfect, it seems we have reached a point where
Kirk = LTP. Therefore, we should reconsider maintaining features
that require updates due to changes in external testing suites.

Signed-off-by: Andrea Cervesato <andrea.cervesato@suse.com>

Author: acerv