docs: add API to footer (Docs column) (#440)

## 📜 Description

Added API link to footer.

## 💡 Motivation and Context

To make API reference page in quick access 🙂 

## 📢 Changelog

<!-- High level overview of important changes -->
<!-- For example: fixed status bar manipulation; added new types
declarations; -->
<!-- If your changes don't affect one of platform/language below - then
remove this platform/language -->

### Docs

- Added API link to footer;

## 🤔 How Has This Been Tested?

On localhost and preview.

## 📸 Screenshots (if appropriate):

<img width="1728" alt="image"
src="https://github.com/kirillzyusko/react-native-keyboard-controller/assets/22820318/95ec0d04-bf46-48dd-8dae-4dfbc2ebdc61">

## 📝 Checklist

- [x] CI successfully passed
- [x] I added new mocks and corresponding unit-tests if library API was
changed

docs/docusaurus.config.js

@@ -136,6 +136,10 @@ const config = {
                 label: "Guides",
                 to: "/docs/installation",
               },
+              {
+                label: "API",
+                to: "/docs/category/api-reference",
+              },
             ],
           },
           {