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;

test/module/ts/package.json

@@ -0,0 +1,20 @@
+{
+  "name": "ts-entrypoint-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "scripts": {
+    "test": "npm i --no-save --no-package-lock && npm run build && node index.js",
+    "build": "tsc"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "MIT",
+  "dependencies": {
+    "@types/node": "^18.11.3",
+    "axios": "file:../../.."
+  },
+  "devDependencies": {
+    "typescript": "^4.8.4"
+  }
+}