Eliminate unnecessary filer address from upload URLs by passing file
paths directly instead of full URLs that get immediately parsed.
Changes:
- Rename genPartUploadUrl() → genPartUploadPath() (returns path only)
- Rename toFilerUrl() → toFilerPath() (returns path only)
- Update putToFiler() to accept filePath instead of uploadUrl
- Remove URL parsing code (no longer needed)
- Remove net/url import (no longer used)
- Keep old function names as deprecated wrappers for compatibility
Benefits:
- Cleaner code - no fake URL construction/parsing
- No dependency on filer address for internal operations
- More accurate naming (these are paths, not URLs)
- Eliminates confusion about HA concerns
This completely removes the filer address from upload operations - it was
never actually used for routing, only parsed for the path.