Update subscription test suite
Update subscription test suite

Changes:
    - Remove test checking if service enable and add in test setup
    - Update documentation and add default remote dummy server IP

This test suite would be use to further write newer event notification
use cases.

Resolves   openbmc/openbmc-test-automation#2162

Change-Id: I506668ae81d108ffe4e7ad7d805b860a7fb70a35
Signed-off-by: George Keishing <bef0a9ecac45fb57611777c8270153994e13fd2e@in.ibm.com>

openbmc/openbmc-test-automation,openbmc/openbmc-test-automation