[FEATURE]: Extract main README contents to separate files

Details

Is your feature request related to a problem? Please describe.

The main README is very long, it might be better to extract some of the information to separate files. I think the main README should serve as an index/pointer to any information you want, and mainly focus on describing the PoC and maybe listing the requirements.

Most of the information added in #140 involves instructions, I think it would be better to extract this to a separate file e.g. INSTRUCTIONS.md/USAGE.md/SETUP.md/GUIDE.md/etc. I'd personally move everything in the "Proof of Concept Edge use case with ACM" section to a separate file(s), apart from this description which would be helpful to have in the main README:

https://github.com/opendatahub-io/ai-edge/blob/0f86d5c8096d3889cada49d8e1b819fd35b327b2/README.md?plain=1#L21-L23

Describe the use-case or expected workflow

graph TB
    A[Main README]
    B[DEVELOPMENT.md]
    C[CONTRIBUTING.md]
    D[GUIDE.md]
    E[pipelines/README.md]
    F[acm/README.md]
    G[pipelines/GITEA.md]

    A -->|What is this repo for/about?| A
    A -->|How do I build more code on top of this repo?| B
    A -->|How can I contribute to this repo?| C
    A -->|How do I set-up and use the code in this repo?| D
    D -->|How do I set-up and use the pipelines code?| E
    D -->|How do I set-up and use the ACM code?| F
    E -.->|What if I want to use on-prem Git?| G

Describe alternatives you've considered

Could just not do anything ¯\(ツ)/¯

Additional context

N/A

opendatahub-io / ai-edge