Removed statsd from the api and use the statsd in the utils library.

The statsd code was added to the utils library a while ago, uses the
statsd from the util library and therefore consolidates the code into
once place.

app/dao/stats_template_usage_by_month_dao.py

@@ -1,7 +1,7 @@
+from notifications_utils.statsd_decorators import statsd
 from sqlalchemy import or_, and_
 
 from app import db
-from app.statsd_decorators import statsd
 from app.dao.dao_utils import transactional
 from app.models import StatsTemplateUsageByMonth, Template