Introduce User Preferences

[fcamblor]

There should be a User Preferences button accessible from User Dashboard screen

At the moment, we should only have 1 option on this screen, allowing to chose which kind of theme to use :

• OS-based theme (default)
• Light theme
• Dark theme

[fcamblor]

Another idea regarding user preference would be to ask if user wants date+time displayed in his local time or in the event's local time.

This should be a per-event preference (not a global user pref).

Why showing date+time in user's (browser) timezone ?
For remove events taking place in a different timezone than yours, it might be relevant to show date & times in your timezone rather than in the event's timezone

Why showing date+time in the event's timezone ?
It allows you to project yourself in local times, regardless of your timezone.
If I'm in France today (UTC+2), and I want to attend (physically) a conference tomorrow in Morocco which is UTC+1, it would be more relevant to show me Morocco times (in UTC+1) instead of France time (UTC+2) otherwise I might get late tomorrow if I don't show the schedule once I am in Morocco.