fix: removes the dependency on dcignore to create the .dcignore files.

[fsargent]

Description

This PR removes the dependency on @deepcode/dcignore as it only serves to create a static file. Instead we source the text from inside this repository, since it's the only place it's used.

After this is merged, we can consider archiving the dcignore repository.

Checklist

• [x] Tests added and all succeed
• [x] Linted
• [-] CHANGELOG.md updated
• [-] README.md updated, if user-facing

Screenshots / GIFs

No visual changes.