Make the BASE file system pluggable

[Nicklas Nordborg]

The BASE file system is already an abstract thing for client applications in the sense that the directory structure and files on disk doesn't map to the BASE directory structure. A client application is never allowed direct access to the real file system.

The file system is however locked to use a local or network mounted disk. If we can make this pluggable it would be possible to implement file storage on, for example, an FTP server. The main benefit from this is that setting up job agents and other external program will be much more flexible.

Various implementation must also be able to work together, since for example the web server may still want to use the local file system.