Automatically create new seasons based on API

[BitTim]

When a new season is due, no longer show the dialog for creating a new season, but rather pull the necessary data from the API (#69) and create the season automatically. Notify the user with a dialog, that a new season has been created.

Event contracts should also be created automatically when available and should also notify the user, that one is available and active.

Similar should also be done with the data init dialog, so that it only takes the current battlepass level and xp within it. Based on this a total collected amount shall be calculated and applied to the "startXP" field of the current season, as decribed in #75