Refactored module exports; (#5162)

* Refactored build pipeline;
Added module exports tests;
Added missing ESM export for parity with Axios factory;
Added `toFormData`, `formToJSON`, `isAxiosError`, `spread`, `isCancel`, `all` as named export to `index.d.ts`;

* Added ESM entry test;

* Updated README.md `installing` section;

* Added TypeScript importing test;
Added missed `CanceledError` & `AxiosHeaders` to `AxiosStatic` interface;

* Exclude `/test/module/` from tslint;

README.md

@@ -35,6 +35,8 @@
   - [Features](#features)
   - [Browser Support](#browser-support)
   - [Installing](#installing)
+    - [Package manager](#package-manager)
+    - [CDN](#cdn)
   - [Example](#example)
   - [Axios API](#axios-api)
   - [Request method aliases](#request-method-aliases)
@@ -93,6 +95,8 @@ Latest ✔ | Latest ✔ | Latest ✔ | Latest ✔ | Latest ✔ | 11 ✔ |
 
 ## Installing
 
+### Package manager
+
 Using npm:
 
 ```bash
@@ -117,7 +121,39 @@ Using pnpm:
 $ pnpm add axios
 ```
 
-Using jsDelivr CDN:
+Once the package is installed, you can import the library using `import` or `require` approach:
+
+```js
+import axios, {isCancel, AxiosError} from 'axios';
+```
+
+You can also use the default export, since the named export is just a re-export from the Axios factory:
+
+```js
+import axios from 'axios';
+
+console.log(axios.isCancel('something'));
+````
+
+If you use `require` for importing, **only default export is available**:
+
+```js
+const axios = require('axios');
+
+console.log(axios.isCancel('something'));
+```
+
+For cases where something went wrong when trying to import a module into a custom or legacy environment,
+you can try importing the module package directly:
+
+```js
+const axios = require('axios/dist/browser/axios.cjs'); // browser commonJS bundle (ES2017)
+// const axios = require('axios/dist/node/axios.cjs'); // node commonJS bundle (ES2017)
+```
+
+### CDN
+
+Using jsDelivr CDN (ES5 UMD browser module):
 
 ```html
 <script src="https://cdn.jsdelivr.net/npm/axios@1.1.2/dist/axios.min.js"></script>
@@ -131,19 +167,11 @@ Using unpkg CDN:
 
 ## Example
 
-### note: CommonJS usage
-In order to gain the TypeScript typings (for intellisense / autocomplete) while using CommonJS imports with `require()` use the following approach:
-
-```js
-const axios = require('axios').default;
-
-// axios.<method> will now provide autocomplete and parameter typings
-```
-
 Performing a `GET` request
 
 ```js
-const axios = require('axios').default;
+import axios from 'axios';
+//const axios = require('axios'); // legacy way
 
 // Make a request for a user with a given ID
 axios.get('/user?ID=12345')