Feature 10961 Addition of external targets to OSM Prometheus

This commit allows the automatic regeneration of a Prometheus config
file from a sidecar by combining the information in PROMETHEUS_BASE_CONFIG_FILE
and the prometheus_jobs in mongo.

Change-Id: I0246d60ec32733a088ca8590a6445735549bf4de
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>
diff --git a/docker/Prometheus/Dockerfile b/docker/Prometheus/Dockerfile
index 7c84207..228f597 100644
--- a/docker/Prometheus/Dockerfile
+++ b/docker/Prometheus/Dockerfile
@@ -21,6 +21,7 @@
 ENV PROMETHEUS_URL http://prometheus:9090
 ENV MONGODB_URL mongodb://mongo:27017
 ENV PROMETHEUS_CONFIG_FILE /etc/prometheus/prometheus.yml
+ENV PROMETHEUS_BASE_CONFIG_FILE /etc/prometheus_base/prometheus.yml
 ENV TARGET_DATABASE osm
 
 WORKDIR /code
@@ -31,4 +32,4 @@
 
 COPY src/app.py .
 
-CMD [ "python", "-u", "./app.py" ]
\ No newline at end of file
+CMD [ "python", "-u", "./app.py" ]