allow exporting trips/routes to a folder

[retoo]

@molobrakos maybe you could take a look if you are interested in this functionality? If so I'd add some better documentation. may be refactor the exporting code into an own file/class and include any feedback/suggestion you have. Up to you.

The idea is to have a longer track of past trips and especially the full routes/waypoints.

Please let me know what you think.

[molobrakos]

Thanks, maybe we can put it in a new export.py?