Adding that saveAs-Function is called for every Adapter before _write (with fallback)

- Adding ID to serialsFiles (if saved file getting another name from adapter)
- Adding saveAs-Function that is called (async) before _write at every Adapter
=> If no saveAs-Function is found at the Adapter, add a dummy one

First part for https://github.com/balderdashy/skipper/issues/12 - the other part is in skipper-disk