Allow to deploy prometheus as standalone service

Now it is able to install proemtheus on host and
use it to scrape data from other prometheuses.

Prod-related: PROD-17350

Change-Id: I11d65920c0e9b685dead22a5551521fa15d13f25
diff --git a/README.rst b/README.rst
index 95be7cc..42ce26d 100644
--- a/README.rst
+++ b/README.rst
@@ -160,6 +160,17 @@
       enabled: true
       external_port: 15012
 
+Install prometheus as service
+-------------------------------------
+
+.. code-block:: yaml
+
+parameters:
+  prometheus:
+    server:
+      is_container: false
+
+
 Documentation and Bugs
 ======================