[Umbrella issue] Restructure Turtles documentation content

[furkatgofurov7]

The current flow in the documents seems somewhat confusing to the Turtles' end users and consumers, so this is an umbrella issue mainly meant to improve the current document's user-friendly and easy-to-follow outline.

Things we could potentially improve:

• Have an A-Z exemplary guide explaining the required steps starting from kind cluster creation til the CAPI cluster is imported into the Rancher Dashboard and visible in UI/CLI running in the infrastructure of certified providers (we might already have some parts of this covered in different places)
• Restructure book sections to make them easy-to-follow and more end-user structured (move out HOW TO/A-Z guides to make them visible instead of hiding them under multiple sub-folders)
• possible have a dedicated section for the Turtles features, each described and followed with 'how to use' example
• Improve the content (rephrase/reword or change completely) to make it easier to read and follow wherever applicable
• Make the docs more visual with extra screenshots/recordings/gifs wherever applicable
• Remove unnecessary/outdated/confusing content