[nexus-sonatype-casc]; Initial Release

[oliverbaehler]

What this PR does:

Adds a new chart to the repository.

Notes for Reviewer:

Checklist:

• [ ] Pull Request title in format [chart]: Changed Something
• [ ] Updated documentation in the README.md.gotmpl file and executed helm-docs
• [ ] Chart Version bumped
• [ ] All commits are signed-off