Filetransfer

- Re-implementation of configuration handling
- Changes in API
- Minor changes in job and host configurations

- Support ECDSA and Ed25519 for SFTP authentication keys
- Change SFTP authentication key configuration
- Remove host configurations from job configuration files

- Improve usage message and documentation

- Some minor corrections
- Improve API

- Bugfix: When using the API in a script only one SFTP transfer succeeded and the others failed.

- First public release.