Add `.js` extension for artifacts import (ESM compatability)

[gilgardosh]

Issue workflow progress

Progress of the issue based on the Contributor Workflow

• [ ] 1. The issue provides a reproduction available on Github, Stackblitz or CodeSandbox

Make sure to fork this template and run yarn generate in the terminal.

Please make sure Mesh package versions under package.json matches yours.

• [ ] 2. A failing test has been provided
• [ ] 3. A local solution has been provided
• [ ] 4. A pull request is pending review

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Describe the bug

Bundling a package with Mesh artifacts as ESM results in error, since the hardcoded paths in the artifacts are missing .js extension

To Reproduce Steps to reproduce the behavior:

1. Create a basic Mesh example with local sources (e.g the json-schema-example)
2. Generate artifact
3. Create ESM bundle
4. Try to run the bundled artifact

Expected behavior

Bundled artifacts should fully support ESM

[gilgardosh]

ESM is currently supported. with the NODE_OPTIONS=\"--loader ts-node/esm\" mesh build command. @ardatan can we maybe migrate this var to the configuration file?