Let's replace some ugly hacks with proper pytest conftest.py hooks.
Test initialization of ipalib.api is now handled in
pytest_cmdline_main(). Pytest plugins, markers and ignores are also
moved into conftest.py. Additional guards make it possible to run tests
without ipaserver installed.

I added confcutdir to ensure that pytest does not leave our project
space. Pytest used pytest.ini or setup.py before but pytest.ini is gone.

Signed-off-by: Christian Heimes <cheimes@redhat.com>
Reviewed-By: Milan Kubik <mkubik@redhat.com>

The pytest.ini file needs to be in or above the directory py.test is called in.
When in IPA project root, this invocation will find ./ipatests/pytest.ini:
    py.test ipatests/
but these will not (they're equivalent):
    py.test .
    py.test
So pytest.ini must be in the project root.

However, setupttols can't include files outside package directories,
so we also need this file to be under ipatests/

Solve the problem by symlinking ./pytest.ini to ipatests/pytest.ini.

https://fedorahosted.org/freeipa/ticket/4610

Reviewed-By: Tomas Babej <tbabej@redhat.com>