containers: Define micromm container

Initially this container can only run the vmalloc performance tests that
are part of the test_vmalloc.ko kernel module. If no parameters are
provided it will run a full set of tests with default parameters and
provide results for each. Alternatively, parameters may be provided to
specify a single specific test case with a set of custom parameters:

suite: micromm
name: vmalloc
params:
  test_case: fix_size_alloc_test
  nr_pages: 1
  huge: false
  nr_loops: 500000

Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>