sys-fs/bcachefs-tools: Add 1.13.0, update 9999

- Switch to signed tarballs provided by Kent (Updated SRC_URI)
- Add verify-sig USE flag
  - Provided by sec-keys/openpgp-keys-kentoverstreet
- Add workaround for symbolic link having the incorrect reference
- Update cargo dependencies
- Add musl dependency for live ebuild

Signed-off-by: Christopher Fore <[email protected]>
Closes: gentoo#38965
Signed-off-by: Florian Schmaus <[email protected]>