Removed people that no longer contribute to the scylladb.git and added/substituted reviewers responsible for maintaining the frontend components.
No need to backport, this is just an information for the github tool.
Closesscylladb/scylladb#20136
* github.com:scylladb/scylladb:
codeowners: add appropriate reviewers to the cluster components
codeowners: add appropriate reviewers to the frontend components
codeowners: fix codeowner names
codeowners: remove non contributors