This widget will replace our usage of GtkFileChooserButton, except that
it has a title label and also it contains GUI implementation for the
SAVE and CREATE_FOLDER actions (unlike the GTK button). Moreover this
widget was removed in GTK4. So it is a good idea to start encapsulating
such GTK widget anyway.
I'm also adding a propwidget function to create such a widget bound to a
GimpParamSpecFile property.
New functions:
- gimp_file_chooser_get_action
- gimp_file_chooser_get_file
- gimp_file_chooser_get_label
- gimp_file_chooser_get_label_widget
- gimp_file_chooser_get_title
- gimp_file_chooser_get_type
- gimp_file_chooser_new
- gimp_file_chooser_set_action
- gimp_file_chooser_set_file
- gimp_file_chooser_set_label
- gimp_file_chooser_set_title
- gimp_prop_file_chooser_new
