fix: module-import get fallback from externalsPresets

[fi3ework]

What kind of change does this PR introduce?

Adding fallback external type for "module-import" type when "module" and "import" are neither applicable.

In #18620, implement "module-import", but the premise is that we're using import or import() for external request, However, for example, if we use require('...'), "module-import" will failed to know which externals type to adopt ("import", "module", or even "node-commonjs"), and it will crash.

The possible options we may want to fall back to:

1. node-commonjs: to let require('path') code could run in Node.js + ESM (this is widely used).
2. import: possibly for some specific reason.
3. module: possibly for some specific reason.
4. commonjs: level the require there, to be bundled by a bundler.

In this PR, using externalsPresets to indicate which external to use as the fallback:

1. when the exteranlsPresets is node.js related (electrons, node, nwjs): use node-commonjs
2. when the exteranlsPresets is web: use module
3. when the exteranlsPresets is webAsync: use import
4. when exteranlsPresets is not assigned or derived, use commonjs

Since the implementation coupled the fallback with externalsPresets, when users want to set all ESM import/import() to module-import and leave other CJS require to node-commonjs, they need to override the node.js built-in externals type to module-import defined by externalsPresets.

There's a left TODO is when user setting multiple externalsPresets category, e.g. { node: true, web: true }. Which one should we choose to use as fallback. Currently using a simple prioritization module > import > node-commonjs.

Did you add tests for your changes?

Yes.

Does this PR introduce a breaking change?

No.

What needs to be documented once your changes are merged?

Update webpack/webpack.js.org#7345 after merged.

[webpack-bot]

For maintainers only:

• This needs to be documented (issue in webpack/webpack.js.org will be filed when merged)
• This needs to be backported to webpack 4 (issue will be created when merged)

[alexander-akait]

Currently using a simple prioritization module > import > node-commonjs.

I am fine with it

[alexander-akait]

Thank you

[fi3ework]

Thank you, I'll update the doc tonight.