Add request handling performance dashboard

This second dashboard helps end users drill down on a particular service and get more golden signals type metrics such as error rate by path and median upstream response time by path.

Signed-off-by: Naseem <naseem@transit.app>

deploy/grafana/dashboards/README.md

@@ -1,19 +1,39 @@
 # Grafana Dashboards
+
 Ingress-nginx supports a rich collection of prometheus metrics.  If you have prometheus and grafana installed on your cluster then prometheus will already be scraping this data due to the `scrape` annotation on the deployment.
 
-This folder contains a dashboard that you can import:
+This folder contains two dashboards that you can import.
+
+## 1. NGINX Ingress Controller
 
 ![Dashboard](screenshot.png)
 
-## Features
+### Features
 
-  - Ability to filter by Namespace, Controller Class and Controller
-  - Visibility of Request Volume, connections, success rates, config reloads and configs out of sync.
-  - Network IO pressure, memory and CPU use
-  - Ingress P50, P95 and P99 percentile response times with IN/OUT throughput
-  - SSL certificate expiry 
-  - Annotational overlays to show when config reloads happened
+- Ability to filter by Namespace, Controller Class and Controller
+- Visibility of Request Volume, connections, success rates, config reloads and configs out of sync.
+- Network IO pressure, memory and CPU use
+- Ingress P50, P95 and P99 percentile response times with IN/OUT throughput
+- SSL certificate expiry
+- Annotational overlays to show when config reloads happened
 
-## Requirements
+### Requirements
 
-  - **Grafana v5.2.0** (or newer)
+- **Grafana v5.2.0** (or newer)
+
+## 2. Request Handling Performance
+
+![Dashboard](request-handling.png)
+
+### Features
+
+- Ability to filter by Ingress
+- P50, P95 and P99 percentile of total request and upstream response times
+- Request volume by path
+- Error volume and error rate by path
+- Average response time by path
+- ...and more
+
+### Requirements
+
+- **Grafana v6.6.0** (or newer)