Improve README

[th0ger]

TLDR; Add screenshot.

[...] help you quickly detect if there's any issue with your application. [...] The tool is running as an extension in the Argo CD UX.

Okay... So what exactly do I get?

Installation
The following steps install Numaproj Assist in your Kubernetes cluster, and run a demo application to show how it works.

Okay, just post a screenshot and a list of top 3 features. But I'll be among the few % to accept the install challenge to see the hidden treasure.

2. Install Prometheus if you don't have one, and configure

$ kubectl apply -f  https://raw.githubusercontent.com/numaproj/numalogic-prometheus/main/manifests/prerequisites/prometheus/install.yaml
error: unable to read URL ..., server reported 404 Not Found, status code=404

Sorry, I give up. Can't spend time on debugging missing resources for software I don't know what is and probably don't need. I do have loads of time to write GH issues though 😆 Jokes aside, I would love to see what this project is about.

[vigith]

@syayi, I am assigning this issue to you for tracking. We need to clean up our demo repo since it has a lot of stale irrelevant examples and deprecated info.