Create a way to automatically sync workouts from devices

[borja]

So, right now we ask users to manually upload fit or gpx files into openworkouts. This is ok for users with a more "techie" background, but not for users with the lack of such knowledge.

So, one idea is to add some code that automatically syncs files from your device (garmin, polar, etc).

1. If openworkouts is running locally, that code could be part of openworkouts code base

2. If users are using openworkouts as a service, we should give this code as a small installable app that acts like a daemon/service, waiting for such device to be connected, then syncing files.

Workflow:

1. Code runs as a daemon/service on the background, monitoring USB and bluetooth connected devices.

2. When a new device is connected, we look for certain patterns in the files available from such device (like the Garmin Activities folder) and then look into files there

3. Then we look into those files, comparing against the existing data in openworkouts, adding new files when needed (hint, maybe storing a cache of saved/stored files somewhere would be a good idea)

Open questions:

1. User identification when running openworkouts in the same computer the device is connected

2. User auth when running the tool in a computer and openworkouts as a service

3. Make it easily extensible, so we can add more devices easier

[borja]

Some links with ideas:

​https://gist.github.com/grantstephens/ea92a638fd79191e251d24d0984ef63f

​https://github.com/La0/garmin-uploader

This may well contain good ideas for ticket #81 too