Make nameserver resolution functions more consistent and accessible:
- Rename currentNameserversFromResolvconf to CurrentNameserversFromResolvconf
- Move function to public API for better reusability
- Update all internal references to use the new public API
- Add comprehensive godoc comments for nameserver functions
- Improve code organization by centralizing DNS resolution logic
This change makes the nameserver resolution functionality more maintainable
and easier to use across different parts of the codebase.
So setting up logging for ctrld binary and ctrld packages could be done
more easily, decouple the required setup for interactive vs daemon
running.
This is the first step toward replacing rs/zerolog libary with a
different logging library.
