Allow FXFileChooser to reuse an existing observable list of paths (or files)

[Oliver-Loeffler]

In certain environments (with folders of 100 000s of files) it might be helpful to run a scheduled task to keep the list of files updated. Therefore it might be useful to have FXFileChooser to work with an externally populated observable list.

Furthermore, provide a scheduled Update service which can be used in Swing and JavaFX applications.

Idea

• Decouple the directory update service from FXFileChooser
• Make FXFileChooser to use this service

Questions

• How to deal with manual refreshing? Hide it and rely only on scheduled refreshes?

[Oliver-Loeffler]

This should be used as of commit 7a681dfca46aeb2407e86d530c59fc1c86dc9f10 but there is no nice creation or builder API around.