Vitepress test branch

[hamishwillee]

This is an initial test build of vitepress build of MAVSDK. You can test it by cloning, and in the root of the installation running

yarn install
yarn build

Then navigate to suggested URL.

It Fixes up sidebars and nav.

Things to do:

• CI
• Fix C++ ref generation to fix up notes/tips/warnings.
• Fix up C++ ref generation or docs to fix errors that I manually "tuned" in 462782e
• Fix up other notes.

@julianoes Have peak when you get a chance. If you think it is more or less heading in the right direction then we can push it further.