Add badges for the Debian packages

[mr-c]

• [ ] Is any new functionality in tested? (This can be checked with make clean diff-cover or the CodeCov report that is automatically generated following a successful CI build.)
• [ ] Was a spellchecker run on the source code and documentation after changes were made?
• [ ] Have any changes to the command-line interface been explicitly described? Only backwards-compatible additions are allowed without a major version increment. Changing file formats also requires a major version number increment.
• [ ] Have any substantial changes been documented in CHANGELOG.md? See keepachangelog for more details.
• [x] Do the changes respect streaming I/O? (Are they tested for streaming I/O?)