Integrate Dioxus Docs Into Docsite

A lot of useful information can be found in https://github.com/DioxusLabs/dioxus/tree/main/packages

First at the `/README` level and secondly at `/docs/*`. I would be worth while if this could be integrated into the docsite and made searchable.

Do do so, I propose that https://github.com/DioxusLabs/dioxus/ become a submodule of this repo and a new section `crates` be added to the docs
```
Crates
├── ...
├── document
│ ├── head
│ ├── eval
├── ...
```

This proposal is related to the third bullet here https://github.com/DioxusLabs/docsite/issues/436

If this proposal and implementation is accepted. I'd be happy to work on it.