added more demo screenshots (open-telemetry#456)

* add more demo screenshots

* added links to images

* updated prometheus image PR feedback

Co-authored-by: Pierre Tessier <pierre@pierretessier.com>

docs/demo_screenshots.md

@@ -1,7 +1,12 @@
 # Demo Screenshots
 
-- [Webstore](#webstore)
-- [Jaeger](#jaeger)
+- [Demo Screenshots](#demo-screenshots)
+  - [Webstore](#webstore)
+  - [Jaeger](#jaeger)
+  - [Prometheus](#prometheus)
+  - [Grafana](#grafana)
+  - [Feature Flag UI](#feature-flag-ui)
+  - [Load Generator UI](#load-generator-ui)
 
 ## Webstore
 
@@ -14,3 +19,25 @@
 | Jaeger UI                                                                                                         | Trace View                                                                                                    |
 | ----------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------ |
 | ![jaeger-ui](https://user-images.githubusercontent.com/15364991/194417029-1e40f276-8785-47fb-b645-c90820c0ff52.png) | ![jaeger-trace-view](https://user-images.githubusercontent.com/15364991/194416769-188acc26-71c9-4611-8150-aa8639f11217.png) |
+
+| System Architecture|
+| --- |
+|![jaeger-system-architecture](https://user-images.githubusercontent.com/47896520/196496223-6d6ea729-5bea-4a8c-a2c6-cd51cce386ae.png)|
+
+## Prometheus
+
+![prometheus](https://user-images.githubusercontent.com/47896520/196564627-ba9f5e91-a0fa-4bf0-beb1-f3a79ca309b5.png)
+
+## Grafana
+
+| Prometheus Data Source |Jaeger Data Source |
+| --- | --- |
+| ![grafana-prometheus](https://user-images.githubusercontent.com/47896520/196495466-86d3ce33-def4-4808-a6d9-3e32934bbf03.png) | ![gragana-jaeger](https://user-images.githubusercontent.com/47896520/196495509-c233d0d9-5e4c-4607-b609-dbf7869298d9.png) |
+
+## Feature Flag UI
+
+![feature-flag-ui](https://user-images.githubusercontent.com/47896520/196496050-22fbbb56-9e62-46dd-a23c-c34c5566f7d2.png)
+
+## Load Generator UI
+
+![load-generator-ui](https://user-images.githubusercontent.com/47896520/196496589-bda802fc-aada-4e72-a184-93bb4711abca.png)