Integration with 11ty

## Describe the feature

To use linaria as a css-in-js solution for `eleventy` https://www.11ty.dev

*maybe it is already feasible, so it is a matter of including it in the docs

## Motivation

11ty is a great static generator that AFAIK lacks modern css-in-js solutions, but linaria should be compatible with it (already?)

So it would be useful to document what is needed to setup linaria with 11ty so that one can include css styles within js 11ty layouts

## Possible implementations

Styles could be located in js template functions(*) and extracted during the build process

(*) https://www.11ty.dev/docs/languages/javascript/#javascript-template-functions