When hovering over an avatar, do not only display local time but also calculate the time difference compared to you (similar to how GitHub does this)

[sorbaugh]

Subtask: #43763

[sorbaugh]

cc @nickvergessen something that is relevant for Talk too?

[nickvergessen]

Will automatically appear in Talk if modified correctly in the LocalTimeProvider

[sorbaugh]

Notes:

• Might need backend work. Judging from nickvergessen's comment this would require "only" a change in one line of code but needs to be tested.
• We need to improve the user popup a bit. There's additional data that could be added. Consensus is generally the user popup could use some love.