Change barometer module to load

Change barometer module to load

As [1] is merged, the way to call the barometer test case is
different as it is hosted in Barometer repo instead of Functest.
The former files are also simply removed too.

baro-tests is no longer a requirement. It is installed as any
third party project.

[1] https://gerrit.opnfv.org/gerrit/#/c/35927/

Co-Authored-By: Cédric Ollivier <cedric.ollivier@orange.com>
Change-Id: Iea56b48fa781600eb3a6ac74662ea8a29f556f99
Signed-off-by: Jose Lausuch <jose.lausuch@ericsson.com>
Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>