Implement `cksum --check`

According to GNU:
```
       -c, --check
              read checksums from the FILEs and check them
```
Tested in GNU with tests/cksum/cksum-a.sh
Source:
https://github.com/uutils/coreutils/blob/main/src/uu/cksum/src/cksum.rs