Add tags to main suite

Add tags to  main suite

when running robot, we got an overall healthcheck results, it could be
interesting to have a view on the core, dcae, multicloud, 3rparty and
API (MSB) to quickly identify the problems and eventually not run some
of the tests if it is known as not supported (e.g. dcae)
This patch does not modify the code of the existing test
It leverags robotframework tagging mechanism

Using the OPNFV functest abstraction it is trivial to run them in CI/CD,
push results to a DB and create a dashboard[1]

this patch does not modify the code of the existing test

[1]: http://testresults.opnfv.org/onap-testing/amsterdam/functest/status-heat.html

Issue-ID: TEST-80

Change-Id: I5090b8c31cc5d42ae43cc04c557a42e072e1653c
Signed-off-by: mrichomme <morgan.richomme@orange.com>