Lack of Local Build Instructions in README.md

[OjaswiJoshi13]

While README.md links to a "Getting Started" guide, it does not contain direct build commands or installation instructions inline.

Add a short "Quick Start" build section with: (Bash/terminal) git clone https://github.com/facebook/infer.git cd infer ./build-infer.sh

Improves DX (developer experience) and encourages first-time contributors to try building it quickly.

[xeodus]

Hey @OjaswiJoshi13, I would like to take this one.

[martintrojer]

#1934