Add web ui authentication

Change-Id: I29c61f84dd8443a650cf45a4a2dfcc99efed1106
Signed-off-by: David Garcia <david.garcia@canonical.com>
diff --git a/installers/charm/prometheus/config.yaml b/installers/charm/prometheus/config.yaml
index 6db6a60..b25eaba 100644
--- a/installers/charm/prometheus/config.yaml
+++ b/installers/charm/prometheus/config.yaml
@@ -75,3 +75,11 @@
     description: Enables the security context of the pods
     type: boolean
     default: false
+  web_config_username:
+    type: string
+    default: admin
+    description: Username to access the Prometheus Web Interface
+  web_config_password:
+    type: string
+    default: admin
+    description: Password to access the Prometheus Web Interface