Add a Troubleshooting and Onboarding Section to Documentation

[adityabhattad2021]

To improve the onboarding experience for new developers, we can create a dedicated "Troubleshooting" section in the repository documentation. This section should:

1. Cover solutions to common issues encountered while setting up the repo.
2. Clarify common assumptions about the codebase and its dependencies.
3. Provide a small video tutorial to visually guide new contributors through the setup process.

[meetjn]

Hi @adityabhattad2021 , Can I work upon this?

[adityabhattad2021]

Yes, sure!

[meetjn]

Quick update:
Troubleshooting and common codebase assumptions are done, now shooting a video for project setting up! @adityabhattad2021

[adityabhattad2021]

Thanks for working on the documentation improvements. However, I suggest first reviewing our Discord support channel history (#fairfund channel) to identify the actual issues developers are facing during setup.

The current PR contains generic troubleshooting steps (especially around Docker and environment setup) that don't address the specific problems our new contributors have been reporting. Rather than writing a general guide, let's document solutions to real issues that have come up repeatedly in Discord.

Once you've had a chance to review the Discord history, we can update this PR to include those specific scenarios, error messages, and their validated solutions.

Let me know if you need help finding the relevant Discord discussions.