DST not respected

[linco95]

When the times change from DST. When the time change is happening, some activities travel back in time to be colliding with existing reservations.
There are some solutions for this:

• Don't put reservations at time period including the time change dates
• Move every reservation by a timestep to avoid the times the change is actually happening (will not work well with different user timezones (don't know user timezone in this tool, so no easy way of knowing how much we need to move them)
• Do the reservations in local timezone of the current system, and assume it is the same as the importing user.