Update the Python Quickstart README

[feorlen]

Improve the Python Quickstart:

• Add a minimal client example
• Clarify the steps to run the file uploader example.
• Update text and formatting to more closely match the MinIO docs.

Since this repo doesn't use the Docs staging server, this direct link in GitHub is an easier way to see an overview of changes than reading the diff:
https://github.com/feorlen/minio-py/blob/readme-quickstart-update/README.md

This update roughly follows the structure of the minio-go README.

Corresponding docs issue: minio/docs#1042

[feorlen]

@balamurugana Appreciate the comments! I will revisit the content with this in mind.

From a documentation perspective, it is helpful to have the examples in the different SDKs be as similar as possible. That doesn't always fit with needs/practices of different languages of course, sometimes takes a bit of experimentation to find the correct balance.

[feorlen]

@balamurugana I've reworked the entire page based on our conversation. I've retained some of the descriptive text and streamlined other parts. When you have a moment, I'd appreciate a look and if this approach seems useful for both less and more knowledgeable types of readers. It's closer to the original, but with some additional context for a novice/casual reader.

[feorlen]

Added and linked to this along with the license

[feorlen]

Perhaps this is more practical, less verbose yet still some additional context for novice readers.

[harshavardhana]

PTAL @balamurugana

[minio-trusted]

PTAL @balamurugana

Bump @balamurugana this is waiting on your review - can you please take a look?