Link to component model and WASI documentation from the site

We should add links to the component model and WASI documentation that the Bytecode Alliance SIG docs has put together. This could improve discoverability of the documentation.

Component model book: https://component-model.bytecodealliance.org/
WASI book: https://wasi.dev

We could quickly add it to the FAQs or Projects page. It may better fit under a new "Learning" tab