docs: fix getting started guide formatting

[karthik-kumarux]

Description

Fix the formatting and readability issues in docs/getting-started.md described in Issue #30.

The guide was rendered incorrectly because of escaped Markdown headings, HTML entities, escaped underscores, excessive blank-line spacing, and malformed code formatting. The examples were checked against the current repository API.

Closes #30

Changes

• Fixed escaped Markdown headings and formatting artifacts in docs/getting-started.md.
• Removed excessive blank-line spacing and normalized Markdown formatting.
• Corrected code blocks and inline code formatting.
• Verified the documented API examples against the current codebase.
• Added Getting Started links to README.md and CONTRIBUTING.md.
• Added a documentation fix entry under [Unreleased] in CHANGELOG.md.

Type of change

• Bug fix
• New feature / integration
• Documentation update
• Refactor / code quality

Checklist

• pytest tests/ -v passes locally
• ruff check ragframework/ passes
• mypy ragframework/ passes
• New or updated tests cover the changes
• Optional dependencies are guarded with a helpful import error
• Docstrings updated where applicable
• CHANGELOG.md updated under [Unreleased]

[karthik-kumarux]

Hi, the PR is ready for review. The GitHub Actions workflows are currently awaiting maintainer approval. Please approve the workflows when convenient so the required checks can run. Thank you!

[adaumsilva]

Good job @karthik-kumarux ! Thanks for the contribution. Remember to star the repo if you didn't yet.