Applied tier0 and tier1 marks on unit tests and xmlrpc tests

Web UI tests were marked as tier1 tests.

The tier system is intended to be used together with CI system
to make sure the more complicated tests are being run only
when all of the basic functionality is working.

The system is using pytest's marker system. E.g. an invocation of
all tier1 tests with listing will look like:

    $ py.test -v -m tier1 ipatests

or in case of out of tree tests:

    $ ipa-run-tests -m tier1

Reviewed-By: Ales 'alich' Marecek <amarecek@redhat.com>

ipatests/test_webui/test_selinuxusermap.py

@@ -27,6 +27,7 @@ import ipatests.test_webui.data_user as user
 import ipatests.test_webui.data_group as group
 import ipatests.test_webui.data_hostgroup as hostgroup
 from ipatests.test_webui.test_host import host_tasks, ENTITY as HOST_ENTITY
+import pytest
 
 ENTITY = 'selinuxusermap'
 PKEY = 'itest-selinuxusermap'
@@ -42,6 +43,7 @@ DATA = {
 }
 
 
+@pytest.mark.tier1
 class test_selinuxusermap(UI_driver):
 
     @screenshot