Add support for AFFile type
To support reading/writing files stored in AF. Read is more important though.
Started from here: https://pisquare.osisoft.com/thread/37635-access-pdftextdoc-files-from-af-server
I want to be able to use AF as a one-stop place to access my Asset Data. Therefore i want to be able to access Files stored in AF to provide this data alongside all other data through the PI Web API.