[Feat] Create a svelte component for instantsearch.js

We applied to DocSearch (https://docsearch.algolia.com) to get a search engine for our documentation.
DoSearch recommend to use @docsearch/js@3, their library built on top of autocomplete.js (from algolia).
This is a javascript library, we will have to create our svelte wrappers / components to use it.

Currently the application to the DocSearch program is on going

