Clarify Python/pip setup instructions in getting_started.rst

[Imama-Kainat]

The "Python and Pip" section in getting_started.rst currently states:

"Managing Python installations can be quite tricky. We highly recommend using pyenv or if you are more comfortable using a package manager, then package managers like Homebrew on Mac or apt on Debian for this."

This text doesn't explain why managing Python installations is tricky. New developers might not understand the need for pyenv or other version management tools. It would be beneficial to explain that different projects (including Kolibri) may require specific Python versions, and that pyenv helps manage these versions effectively.

Suggested improvement:

"Managing Python installations can be challenging because different projects may require different Python versions. Using a tool like pyenv is highly recommended as it allows you to easily switch between Python versions. If you prefer using a package manager, you can use Homebrew on macOS or apt on Debian."

It might also be helpful to briefly explain what pyenv does (e.g., "pyenv is a tool that allows you to install and manage multiple Python versions on your system").

[Imama-Kainat]

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