New File Uploader: file upload registration in tusd
Summary
After changing the protobuf (caosdb-proto#24)
- Implement receiving extended FileUploadRequests (+ test)
- Implement registration of file upload in tusd (+ test)
- Implement giving out upload URL for tus clients (+ test)
- Handle unreachable tusd (+ test)
- Add settings in server.conf for tusd (url pattern, proxy, port, ...)
- Update docs?