ipatests: Collect all logs on all Unix hosts
    
    Each integration test entity sets up its own list of logfiles.
    This is made by calling the callback of host's 'collect_log',
    which knows nothing about the context of execution: whether it's
    the test class scope or the test method one. Of course, in this
    case one-time collection of test method log is not supported
    because the logs tracker collects only test class logs.
        In the meantime, almost all the entities (except 'client')
    collect identical logs. Besides, due to the IPA roles
    transformation an each IPA host can become master, replica or
    client, all of these, in turn, can have subroles. So, the
    most common case is the collection of all the possible logs from
    all the IPA (Unix) hosts. However, the customization of a logfiles
    collection is possible.
        The collection is performed with the help of 'integration_logs'
    fixture. For example, to add a logfile to list of logs on a test
    completion one should add the dependency on this fixture and call
    its 'collect_method_log' method.
        ```
        class TestFoo(IntegrationTest):
            def test_foo(self):
                pass
    
            def test_bar(self, integration_logs):
                integration_logs.collect_method_log(self.master, '/logfile')
        ```
        Collected logs:
        1) 'test_foo' - default logs
        2) 'test_bar' - default logs + /logfile
        3) 'TestFoo' - default logs
    
    Fixes: https://pagure.io/freeipa/issue/8265
    Signed-off-by: Stanislav Levin <slev@altlinux.org>
    Reviewed-By: Rob Crittenden <rcritten@redhat.com>