update check

currently it has NO autoupdate function available, it is already included but disabled by definition variable.

- first version info will be fetched on first login
- version info will be reseted on pressing download button and setted to newest version after the user who has initiated the download logs in to codiad again
(don't know any better way to get version manually)
- version info will be stored in /data or /components/update (depends on write permissions), this is needed for adding autoupdate later on

please try it out and give any kind of feedback :) for testing please change version to some older commit sha at one of both locations mentioned above