Improve Overview, Tutorials, and Guides for lakeFS Python SDK

[nopcoder]

Context:

Feedback suggests that the existing documentation does not sufficiently demonstrate practical usage of the lakeFS Python SDK or provide clear, task-focused examples.

Slack reference: https://lakefs.slack.com/archives/C01APUNTSGH/p1740305114751379

Proposed Solution:

Revise and expand the documentation to help users better understand and apply the lakeFS Python SDK in real-world scenarios.

Suggested Structure:

• Overview
  • High-level description of the SDK and its capabilities.
  • Key features and relevant links by user role (e.g., developers).
  • Getting started: installation steps and requirements.
• Tutorials / User Guides
  • Step-by-step guides focused on specific tasks.
  • Examples based on real-world use cases.
  • Coverage of error handling patterns and tips.
• Best Practices and Performance
  • Guidance on optimizing upload/download performance.
  • Comparison of different methods, such as using boto3 with or without presigned URLs.

[ozkatz]

@nopcoder let's separate the guides/overview (product task) from the reference (R&D task)