feat(enable): add cmd to enable features

[jpsc]

Overview

This PR adds a new enable|disable command to the NuxtHub CLI that allows users to easily enable/disable specific NuxtHub features in their Nuxt projects.

closes #25

Features

• Added enable|disable command to activate/deactivate NuxtHub features by modifying the project's nuxt.config.js file
• Supports various features: ai, autorag, blob, browser, cache, database, kv, openapi, realtime, vectorize
• Handles both creating a new config file and updating an existing one
• Provides helpful documentation links after enabling a feature
• Includes special handling for features requiring additional configuration
• Updated docs

Usage

nuxthub enable <feature>
nuxthub disable <feature>

[jpsc]

I was thinking and this could also make sense as a multi select prompt where you can add or remove the features.

Let me know if that makes more sense