WIP - Feat: anomaly detection

[DiegoGuidaF]

Add anomaly detection feature. Since the main issue with the PulseWeaver security model is having unexpected users that share the same IP, I want to have some form of anomaly detection (purely statistic for now which I think should be more than enough in most cases). These anomalies would be something like

• Denied traffic from an IP that was assigned to a user & device but expired - This means a user had an IP they were still using expired
• Traffic from another country that is not the usual for a user - This means we might have some issue or the user travelled (VPN could also be the case in most cases)
• Traffic from the same IP but an unusual user-agent header for it
• ... more cases as I implement & think about it

For now this PR has only the backend, but the frontend will be able to show them and a notification system is planned later to properly notify administrators and allow them to react quickly.

[x] - Backend with main anomalies that should be notified

[] - Frontend showing the anomalies and allowing/suggesting an action