CLI readme: Replace default model & link to wiki

[cosmic-snow]

Update CLI readme.

Describe your changes

• Mistral Instruct has been made the default a while ago with #1564
• Info from old documentation moved to the wiki page: Python-CLI

Issue ticket number and link

N/A

Checklist before requesting a review

• [x] I have performed a self-review of my code.
• [ ] If it is a core feature, I have added thorough tests.
• [ ] I have added thorough documentation for my code.
• [x] I have tagged PR with relevant project labels. I acknowledge that a PR without labels may be dismissed.
• [ ] If this PR addresses a bug, I have provided both a screenshot/video of the original bug and the working solution.

Demo

N/A

Steps to Reproduce

Just compare, it's outdated.

Notes

Live link to new wiki page: Python CLI