define Sl services for DevopsPortal

configure proxy, endpoints

related bug: https://mirantis.jira.com/browse/PROD-15068
Change-Id: I2296430522a1edfe1ad0717ef8f72f297acb89e8
diff --git a/.releasenotes/notes/custom-path-proxy-7f587526696c0744.yaml b/.releasenotes/notes/custom-path-proxy-7f587526696c0744.yaml
new file mode 100644
index 0000000..6f16e07
--- /dev/null
+++ b/.releasenotes/notes/custom-path-proxy-7f587526696c0744.yaml
@@ -0,0 +1,30 @@
+---
+summary: >
+  Additional path for DevopsPortal nginx proxy service
+
+features:
+   - |
+     Possibility of defining additional path to service endpoints. Need to define 'custom_path' variable on system level metadata.
+     Result of endpoint looks like 'address:port/custom_path'. Main goal of this feature - auto loading special frame on DevopsPortal dashboard.
+
+     Example:
+     .. code-block:: yaml
+     parameters:
+       _param:
+         grafana_prometheus_ssl:
+           enabled: false
+       devops_portal:
+         config:
+           service:
+             stacklight-prometheus:
+               configure_proxy: false
+               enabled: true
+               endpoint:
+                 address: ${_param:grafana_prometheus_address}
+                 custom_path: alerts
+                 port: ${_param:grafana_prometheus_port}
+                 https: ${_param:grafana_prometheus_ssl:enabled}
+
+
+fixes:
+  - related bug: https://mirantis.jira.com/browse/PROD-15068