feat: Migrate documentation to Mintlify with enhanced content

[Arthur-Kamau]

This PR migrates our documentation from Docusaurus to Mintlify, introducing a more modern and user-friendly experience.

Key highlights include:
- Platform Upgrade: Transition to Mintlify for a prettier, more intuitive documentation site.
- Improved V3 Docs: Existing Version 3 documentation has been significantly enhanced with more detail and
clarity.
- New V4 Docs: Comprehensive documentation for Version 4 is now available.
- Richer Examples: We've added numerous examples throughout the documentation to better illustrate concepts and
usage.

[dalmasonto]

1. There is a huge gap, maybe a missing image on this page

http://localhost:3000/quickstart#rust-v4

Same issue on same link

2. Encoding issue

There is some encoding issue here http://localhost:3000/schema_reference/signing_revision

Also http://localhost:3000/schema_reference/link_revision

3. Primary color issue (Not huge but noticeable)
   Here it uses blue yet primary color is green

Same on checkout aquafier button on the top navigation on hover, the underline is blue, should be white to match text color or green for primary color

Overal suggestion: Dark and light mode should use green as primary color. Currently, dark mode uses green while light mode uses blue as shown below

The links here are green but if you go light mode

Active link goes orange like and the color remains blue instead of dark(black) meaning it shows visited links as blue yet we don't have the same on dark mode (No visited links on dark mode)

4. Suggestion: The api/schema reference title should have v4 slug to show its specifically for v4

The docs are okay, just a few minor changes on UI side and will be good to go