docs: add docusaurus docs with typedoc

[simoneb]

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Spike to add documentation and API docs website via docusaurus and typedoc.

The website is built with a new GH workflow and automatically deployed to GitHub Pages, accessible at https://nearform.github.io/fast-jwt/ (the API section especially, which is auto generated by typedoc).

The documentation website simply contains the README of the repo and API documentation automatically generated via typedoc.

TODO

• [ ] restrict the docs deployment to pushes to the master branch