Fix support dev server false

[alexander-akait]

This PR contains a:

• bugfix
• new feature
• code refactor
• test update
• documentation update
• typo fix
• metadata update

Motivation / Use-Case

ref webpack/webpack-cli#4045

Breaking Changes

No

Additional Info

When you have devServer: false in your multi comiler mode we will just watch and do not server, so you can use something like:

const path = require("path");

module.exports = [
  {
    target: "webworker",
    mode: "development",
    entry: "./workers/worker.js",
    output: {
      path: path.resolve(__dirname, `public`),
    },
    devServer: false,
  },
  {
    devtool: false,
    mode: "development",
    entry: "./entries/entry1.js",
    output: {
      path: path.resolve(__dirname, `static`),
      publicPath: "/static/"
    },
    devServer: {
      host: "localhost",
    },
  },
];

Useful when you have something what should just bundle and handle like static content - https://expressjs.com/en/starter/static-files.html

[codecov]

Codecov Report

Attention: Patch coverage is 92.30769% with 1 line in your changes missing coverage. Please review.

Project coverage is 96.05%. Comparing base (fdd8801) to head (c2f040a).
Report is 1 commits behind head on master.

Files	Patch %	Lines
src/utils/setupWriteToDisk.js	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1921      +/-   ##
==========================================
- Coverage   96.14%   96.05%   -0.10%     
==========================================
  Files          13       13              
  Lines         831      837       +6     
  Branches      228      233       +5     
==========================================
+ Hits          799      804       +5     
- Misses         32       33       +1     

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