Amazfit sportdata exporter 2.0

This is rewriten version of my previous app with some new features.

• App is able to check new version on github
• Possibility to export unknown workout
• Record with 0 BMP is ignored
• Less space usage - now only backup files remains. Any other export deletes temp folder and so it deletes also ,tar file and extracted folder.
• Better inside code with more reliability
• Bug fixes

note: "Exported workouts" folder will be created after first run of app. They are not included in archive.