Implement Streak feature

[IngmarM]

A streak shall award people that access the platform regularily:

• Streak should be on weekly basis: check that a user logs in at least once a week
• The status should be shown in a profile picture (e.g. as small tag next to the pic / around the picture).
• There should be extra features only for people with streak (exact features tbd)
• Streak information should be shown in the weekly digest

[maurices3001]

• User can see the exact number of consecutive active days (Streak) on InnoVerse.
• The number(Streak) is displayed next to the profile picture.
• Background graphic of the number(streak): flame or something similar.

• Other users cannot see this exact number (streak).
• Upon reaching a streak of 1 week (weekdays only, weekends excluded), the user receives a "Power User" badge on their profile picture.
• The "Power User" badge is visible to all users.
• Upon receiving the "Power User" badge, the user also receives a new emoji called "Innoflamme."
• "Innoflamme" can be used to react to all posts, news, comments, discussions, etc.
• User is informed with a short message box that the "Power User" badge and "Innoflamme" feature have been unlocked for them.