fixtures: change infrustructure scope to function

This should help make tests truly standalone cases.

foris_controller_testtools/fixtures.py

 #
 # foris-controller-testtools
-# Copyright (C) 2018, 2020 CZ.NIC, z.s.p.o. (http://www.nic.cz/)
+# Copyright (C) 2018, 2020-2021 CZ.NIC, z.s.p.o. (http://www.nic.cz/)
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -171,7 +171,7 @@ def cmdline_script_root():
     )
 
 
-@pytest.fixture(scope="module")
+@pytest.fixture(scope="function")
 def infrastructure(
     request,
     backend,
@@ -330,7 +330,7 @@ def updater_languages():
         pass
 
 
-@pytest.fixture(scope="module")
+@pytest.fixture(scope="function")
 def notify_cmd(infrastructure):
     def notify(module, action, data, validate=True):
         args = ["foris-notify", "-m", module, "-a", action]
@@ -350,7 +350,7 @@ def notify_cmd(infrastructure):
     yield notify
 
 
-@pytest.fixture(scope="module")
+@pytest.fixture(scope="function")
 def notify_api(extra_module_paths, infrastructure):
     if infrastructure.name == "ubus":
         from foris_controller.buses.ubus import UbusNotificationSender