Add more alert details to incidentd header.

+ Add metric_id, dimension, metric_value in the incident report header
  to make it easier to identify an anomaly.
+ In case there is a uid in the dimension, put the its package info in the header too

Test: statsd_test && tested locally with a config

Change-Id: I762a1a4b0563fb3104e0d32b616b4a2367485e48