[Workbench] [API] Support UTF-8 filenames and stream names in all manifest-handling code.
Acceptance: a "special file" (a file with special characters in its filename) should be handled in the following cases.
- store in Keep using arv-put
- source file/directory name has special chars
- --filename arg has special chars
- list and read special file using arv-ls, arv-get, arv-mount
- show special file in Workbench
- upload special file in Workbench
- make collection with CollectionWriter
- read collection with CollectionReader