Issue/feature addressed

Removing the Debian-Buster from the CI and Packaging

Proposed solution

Removing the associated commands and files from gitlba-ci.yml and packaging.yml and also docker/packaging

Related commands to Buster are removed from

And docker/packaging/Dockerfile-debian-buster file is removed

Userguid will be updated in another merge request as it also need some additional clean up for other packages

~~Functions and classes, or changes to them, are documented.~~
~~User guide/documentation is updated.~~
Changelog is updated.
~~Suitable tests added for new functionality.~~
~~Contributed code is correctly formatted. (See the ~~contributing guidelines~~).~~
~~License added to any new files~~.
No extraneous files have been added (e.g. compiler output or test data files).