Create simple application log

[geraldhiller]

Let's keep it as simple as possible for now and simply log all important packobot actions to packobot.log. This looks like decent enough candidate: https://www.npmjs.com/package/electron-log

Things we should log:

• [ ] Initialization
• [ ] Found pack(s) in log file
• [ ] Wrote pack(s) to pack store (only pack id, region and status)
• [ ] Status change in pack store (only pack id, region and status)
• [ ] Starting send request (with some kind of process id)
• [ ] Status change of send request (so we can follow the steps of the retry chain)
• [ ] Pack deletion in packs store
• [ ] Token change
• [ ] All errors