Clean up duplicate workflow files

- Remove old complex reframe-release.yml (171 lines)
- Keep new simple release-reframe.yml (20 lines)
- Maintain clean structure with reusable workflows

Current structure:
- 1 reusable workflow (rust-release-reusable.yml)
- 6 simple trigger workflows (release-*.yml)
- 1 workspace handler (release-workspace.yml)
- 1 bulk release workflow (triggers/release-all.yml)
- 2 templates for repositories

Author: shankar-gpio