docs,api-ref: added search filters (#4830)

* initial implementation of search modal

* added hit and search suggestions

* added support for multiple indices

* updated sample env

* added close when click outside dropdown

* test for mobile

* added mobile design

* added shortcut

* dark mode fixes

* added search to docs

* added plugins filter

* added React import

* moved filters to configurations

* handled error on page load

* change suggestion text

* removed hits limit

* handle select all

* open link in current tab

* change highlight colors

* added support for shortcuts + auto focus

* change header and footer

* redesigned search ui

www/api-reference/package.json

@@ -42,6 +42,7 @@
     "prism-react-renderer": "^2.0.6",
     "react": "latest",
     "react-dom": "latest",
+    "react-instantsearch": "^7.0.1",
     "react-intersection-observer": "^9.5.2",
     "react-tooltip": "^5.19.0",
     "react-transition-group": "^4.4.5",