Add Open With file workspace support

[anilbeyazoglu]

Summary

• register the editor for code and text documents and forward macOS Open With events into the app
• collect files outside added projects in an independent pathless Other Open Files workspace
• require the Add project folder chooser when no project or external-file workspace is open
• keep editor, explorer, tab, and terminal state scoped to the active project

Verification

• npm run check
• npm test (17/17 tests passed)
• npm run build
• Native SDK automation smoke test for the zero-project startup dialog and hidden main workspace

[github-actions]

Thanks for the pull request!

Docyrus Open IDE is public to read and install, but while the project settles we
merge changes only from members of the Docyrus organization.
A maintainer will take a look and let you know whether we can accept this patch,
or suggest opening an issue to discuss it first.

See CONTRIBUTING.md for the current policy.