Add durations to pytest run

[pedro-psb]

Sometimes it's useful to know how long an individual test took to run on CI.

A recent case involved a sync to an amazon repository on pulp_rpm, which we are considering skipping depending on it's cost (because it's a pretty edgy case). On my machine this particular test took more than the whole CI run, so checking this timing locally was misleading.

Pytest has a builtin option to list those duration after a test session, which I think we could add to our pytest call.

It looks like this:

# --durations=0 list all test durations after each session
> pytest --durations=0 -v
==================================================================== test session starts =====================================================================
platform linux -- Python 3.12.4, pytest-8.3.3, pluggy-1.5.0 -- /tmp/foo/venv/bin/python
cachedir: .pytest_cache
rootdir: /tmp/foo
plugins: xdist-3.6.1
16 workers [4 items]
scheduling tests via LoadScheduling

test_foo.py::test_long
test_foo.py::test_bar
test_foo.py::test_bar3
test_foo.py::test_bar2
[gw1] [ 25%] SKIPPED test_foo.py::test_long
[gw0] [ 50%] PASSED test_foo.py::test_bar
[gw3] [ 75%] PASSED test_foo.py::test_bar3
[gw2] [100%] PASSED test_foo.py::test_bar2

===================================================================== slowest durations ======================================================================
2.00s call     test_foo.py::test_bar2
1.50s call     test_foo.py::test_bar3
1.00s call     test_foo.py::test_bar

(8 durations < 0.005s hidden.  Use -vv to show these durations.)
================================================================ 3 passed, 1 skipped in 3.91s ================================================================

I'm open to any objections.

[pedro-psb]

Hmm, we do use that --durations in the performance test, so this was probably considered before.
Still, wanna hear opinions.