Bv2.7.5

[Freudenberger]

Features:

• new flashpost alerts
• new games - chaotic pong and brick breaker
• new practice pages and some improvements on existing ones
• feature toggle - user soft delete

Fixes:

• surname during registration (-) #45
• weather data on /data/ endpoint (possible breaking change! but rather minor cause this endpoint wasn't publicly used)
• minor vulnerabilities
• styling