tracking export prototype
fix export status display
improve export performance
refactor: move im/exporter classes to directories

… to simplify adding other im/exporter classes
refactor: move tracking exporter to separate class
refactor: introduce import init
fix: close file after import
add download intent import
reactivate im/export of geo and UA data

It’s few enough data to be handled by the basic im/export system
display maximum upload size
refactor: rename ex/importer classes (again)