ftests: Add a test to get/set cgroup.type

ftests: Add a test to get/set cgroup.type

Add a functional test that can get/set cgroup.type on a
cgroup v2 filesystem.

-----------------------------------------------------------------
Test Results:
        Run Date:                          Dec 06 14:40:46
        Passed:                                  1 test(s)
        Skipped:                                 0 test(s)
        Failed:                                  0 test(s)
-----------------------------------------------------------------
Timing Results:
        Test                             Time (sec)
        -------------------------------------------
        setup                                  0.00
        035-cgset-set_cgroup_type.py           2.30
        teardown                               0.00
        -------------------------------------------
        Total Run Time                         2.30

Signed-off-by: Tom Hromatka <tom.hromatka@oracle.com>