### What problem does this PR solve?
- Adjust <Input> component a suitable horizontal padding when have
prefix or suffix icon
- Slightly change visual effect of <ThemeSwitch> in admin UI
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
### What problem does this PR solve?
- Modify and adjust styles (CSS vars, components) to match the design
system
- Adjust file and directory structure of admin UI
### Type of change
- [x] Refactoring
### What problem does this PR solve?
Add whitelist management and role management in Admin UI
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
