Standalone Package to convert to Bruno collection

[thim81]

Description

Linked to #2340

Provide the Bruno importers (located now in /bruno-app/src/utils/importers) as a standalone package, that can be published as a NPM package.

This would allow open-source tools to import and use the import functions to convert Postman, OpenAPI, ... programmatically to BRU files, which can be used via the Bruno App and Bruno CLI.

Support conversion from:

• Postman collection
• Insomnia collection
• OpenAPI specification
• Postman environment

To Bruno collection

Contribution Checklist:

• The pull request only addresses one issue or adds one feature.
• The pull request does not introduce any breaking changes
• I have added screenshots or gifs to help explain the change if applicable.
• I have read the contribution guidelines.
• Create an issue and link to the pull request.

Note: Keeping the PR small and focused helps make it easier to review and merge. If you have multiple changes you want to make, please consider submitting them as separate pull requests.

Publishing to New Package Managers

Please see here for more information.