[Docs] Add "Local Development Setup" instructions to README

[MayukhPal]

Description
Currently, the README.md lacks clear instructions on how to run the services locally. New contributors (like myself) often face crashes because the default database configuration isn't documented or set up for local testing.

Proposed Change
I have successfully set up the login-service locally using an H2 in-memory database. I would like to add a "Getting Started / Local Setup" section to the README that explains:

1. Prerequisites (Java version, Maven).
2. How to run the application using the new H2 profile/configuration.
3. How to access the H2 Console for debugging.

Why this is needed
To help new contributors onboard faster and avoid "Connection Refused" errors when they try to run the project for the first time.

Assignee
I have already documented these steps while fixing the startup crash. Please assign this to me so I can update the README.

[Jaidhuria]

@MayukhPal hey please assign it to me Under SWoC i'll surely love to work on it and merge the pr too. Thanks

[MayukhPal]

Hi @Jaidhuria , thanks for the interest, but I created this issue specifically to document the changes I made in my previous PR (the H2 database fix). I already have the documentation written and I am just waiting for the assignment to push the PR.

@Manoj-14 I am ready to proceed with this as discussed.