Allow configuration of prometheus server in absence of endpoint dashboard (stratos deployed as cf app)

As a stratos operator deploying stratos in cloudfoundry , in order to enable display of prometheus metrics as documented in docs/bosh-metrics.md, I need a way to configure the prometheus endpoint into stratos

Frontend Deployment type

Where is the frontend deployed?

• [x ] Cloud Foundry Application (cf push)

Backend (Jet Stream) Deployment type

Where is the backend deployed? -->

• [x ] Cloud Foundry Application (cf push)

Expected behaviour

Either:

• an environment variable in manifest.yml (preferred) that enables static configuration of the prometheus endpoint. This would avoid requiring interactive configuration with potential durability issues if stratos not configured with a persistent data store
• an alternative to the "endpoint dashboard", as it is not available in CF-deployed stratos as documented in https://github.com/cloudfoundry-incubator/stratos/blob/v2-master/docs/overview.md#deployed-in-cloud-foundry-as-an-application

In this case, Stratos is deployed in a manner optimized for the management of a single Cloud Foundry instance. The 'Endpoints Dashboard' that allows multiple Cloud Foundry endpoints to be registered is not deployed.

Actual behaviour

Endpoint dashboard not displayed.

• https://github.com/cloudfoundry-incubator/stratos/tree/v2-master/deploy/cloud-foundry#Deploy-Stratos-from-source

Possibly support env var to configure prometheus endpoint is hard to discover

• https://github.com/cloudfoundry-incubator/stratos/blob/v2-master/manifest.yml does not provide the env var as example
• searching prometheus did not return obvious env var I noticed yet https://github.com/cloudfoundry-incubator/stratos/search?q=prometheus&unscoped_q=prometheus

Start with docs/bosh-metrics.md and the Cloud Foundry deployment guidance in deploy/cloud-foundry and docs/overview.md, then inspect manifest.yml for existing configuration examples. Determine how a CF-deployed Stratos instance can configure the Prometheus endpoint without the endpoint dashboard; done means the configuration is discoverable and works for this deployment mode.