[BUG] Offer times are displayed in wrong time zones

[holtvogt]

Circumstances
Currently, a user from a different time zone than the user who created the offer won't receive the converted time when the offer actually takes place. The user, who participates in an offer, receives the time in the time zone of the offer creator.

How to Reproduce
Steps to reproduce the behavior:

1. Be in a different time zone than the user who created the offer you want to participate in
2. See the time from the perspective of the creator

Expected behavior
The offer times should be converted to the user time zones.