refactor: more ES6 code and code improvements

[alexander-akait]

Summary

Refactor core:

1. Using node: prefix for NodeJS modules (good practice, compatibility with deno/bun/other env)
2. Adding js/jsx extensions for import (good practice, less time for resolving in any tools, nodejs/typescript/react/etc strongly recommend to use extensions in imports)
3. Order import(s)/require(s) by alphabet for better readable
4. Use for of instead forEach (for of is faster)
5. Use hasOwn built-in ES6 feature
6. Use template literal
7. Use module.exports at the bottom of files for readable
8. Use better names for one characters variables
9. Use catch without _err where we don't need it
10. Avoid else where it unnecessary
11. Use { for multi-line if
12. Simplify code in some places - use arrow functions, use ternary, use new logic operators

What kind of change does this PR introduce?

refactor

Did you add tests for your changes?

Existing

Does this PR introduce a breaking change?

No

If relevant, what needs to be documented once your changes are merged or what have you already documented?

Nothing

[alexander-akait]

@valscion Ready for review

It is a part of refactor tasks and many changes done to avoid big diff after migration to eslint-config-webpack

[valscion]

Phew that was a lot of code changes to read but I did read all of that.

Only found one nitpick. Let's fix it and then we can merge

[valscion]

JSdoc now in wrong location

[alexander-akait]

@valscion Done 👍