Add ESModules import support

[lundibundi]

• code is properly formatted (npm run fmt)
• documentation is updated (npm run doc to regenerate documentation based on comments)
• description of changes is added under the Unreleased header in CHANGELOG.md

Also, when 'Conditional exports' are no longer experimental the package.json could be changed to use

  "exports": {
    "require": "./common.js",
    "import": "./common.mjs"
  },

to automativally resolve '@metarhia/common' depending on require or import usage. (without the need to use @metahia/common/module)

/cc @nechaido @tshemsedinov

[tshemsedinov]

I don't like esmodules but let it be 😄

[nechaido]

RSLGTM

[lundibundi]

ping @belochub.

[lundibundi]

ping @belochub

[belochub]

LGTM with a small suggestion.

[belochub]

Landed in 94df329.

[belochub]

As it turns out, this PR has introduced a regression by breaking support for importing submodules (e.g. require('@metarhia/common/lib/id')) in latest Node.js versions. As such, unless another commit fixing this will be introduced before the next minor release, this feature will only be made available in the next major release.

[lundibundi]

Should be fixed with #336.