Fix/exclude dirs for webpack

[ElenaDiachenko]

Description

• webpack does not exclude src/pages when bundling code for web platforms that do not use next.js.
• improved webpack merging

Related issues

• GH issues

Npm releases

n/a

[ElenaDiachenko]

@pauliusguzas
Steps for checking:

1. Create a new project with support for macos
2. Run macos => expected issue:

TS2307: Cannot find module 'next/document' or its corresponding type declarations.
  > 1 | import Document, { Html, Head, Main, NextScript } from 'next/document';
      |                                                        ^^^^^^^^^^^^^^^
    2 | import React from 'react';
    3 | import { CONFIG } from '../config';
    4 | 

3. Do rnv link.
4. Run macos again => successfully and without error