unittest: moves test-procedure to component repo

Adds a section to component/Distro-Version.rpms.yml that describes how
a component should be tested and what files need to be archived.

For e.g.:
test_env:
  rpm:
    run: >
      ./run_tests.sh -N -P  >../logs/testrun.log 2>&1
    archive:
      - ../logs/testrun.log
      - horizon/nosetest.xml
  venv:
    run: >
      ./run_tests.sh -V -P  >../logs/venv-testrun.log 2>&1
    archive:
      - ../logs/venv-testrun.log

The above settings run run_tests.sh -N -P when tests are run using only
rpms and run_tests -V -P when tested using pip packages. 'archive'
indicates what files need to be archived after the run.

Change-Id: I3228e9f837cd5a0c5c7261b5b1dbc3a3e387530a