Add sponsorship and storage string resources

- Added `report_issue` string resource.
- Introduced a comprehensive set of string resources for the "Sponsor" feature, including GitHub Sponsors, Buy Me a Coffee, and KotlinConf 2026 voting information.
- Added storage-related string resources for clearing cache and displaying current size.
- Standardized indentation across the `strings.xml` file.
- Added new sorting and label strings (`sort_order_descending`, `sort_order_ascending`, `sort_label`).

Author: rainxchzed