Update file selection boxes to use a GtkFileChooserDialog.

[David Hampton]

Log Message:
-----------
Update file selection boxes to use a GtkFileChooserDialog.  Reinstate
file filtering in the dialog.  Patch from Arnout 'raboof' Engelen.
Fixes #116205.

Tags:
----
gnucash-gnome2-dev

Modified Files:
--------------
    gnucash/src/business/business-gnome:
        gnc-plugin-business.c
    gnucash/src/gnome:
        dialog-chart-export.c
    gnucash/src/gnome-utils:
        gnc-file.c
        gnc-file.h
    gnucash/src/import-export/log-replay:
        gnc-log-replay.c
    gnucash/src/import-export/mt940:
        gnc-mt940-import.c
    gnucash/src/import-export/ofx:
        gnc-ofx-import.c
    gnucash/src/import-export/qif-import:
        druid-qif-import.c
    gnucash/src/report/report-gnome:
        gnc-plugin-page-report.c