fileservice: various changes

[reusee]

What type of PR is this?

• [ ] API-change
• [ ] BUG
• [x] Improvement
• [ ] Documentation
• [ ] Feature
• [ ] Test and CI
• [ ] Code Refactoring

Which issue(s) this PR fixes:

issue #2716

What this PR does / why we need it:

fileservice: refactor testBlockMapper

fileservice: use CRC32 since most CPU has crc32 instructions

fileservice: rename BlockMappable to FileLike

fileservice: rename BlockMapper to FileWithChecksum

fileservice: ignore ignored io entries in S3 bytes-range calculation