Clean up extension creator - add rancher annotations to pkg.package.json

[jordojordo]

Summary

Fixes #12094

Ties up a few loose ends with the extension creator:

• Moved the rancher annotations to the correct package.json file for extension packages
• Removed unnecessary dependencies from the pkg.package.json template and pkg creator package.json
• Removed chart.yaml annotations for extension helm chart.

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[aalves08]

LGTM