Fix the Alarm documentation of Web API V2

Correct the Alarm example on the API documentation to contain a
valid Alarm sample and complete the Note section with information
about the connection between the type and rules fields of the
Alarm.

Fixes bug #1245362

Change-Id: Id7209d3f7a7ab29a50bdb1dfbe90937b1c7c6c8d
Merge "Fix the Alarm documentation of Web API V2"