Publish a minimal documentation website

[niksirbi]

Minima requirements:

• installation instructions (for users and dev), probably with uv
• API index
• Sphinx gallery

[niksirbi]

We have a working website at https://neuroinformatics.dev/poseinterface/ but it's lacking installation instructions and the examples gallery is empty.

We should also transfer it to https://poseinterface.neuroinformatics.dev/ to match the pattern of our other website.

[niksirbi]

We decided to include an example converting a session from a DLC project to our poseinterface format.