Add time stamps to calls

### Your use case

#### What would you like to do?

Add time stamp to calls

#### Why would you like to do it?

I would like to know when someone (may be me) called

#### How would you like to achieve it?

Add a time stamp next to the call "widget" like any other message has it.
Timestamp = call was initiated

### Have you considered any alternatives?

Alternative;
- multiple time stamps (call initiation, call established)
- show the time stamp when the call was established
- add the time stamp to the call "widget" itself

### Additional context

Currently there are no time stamps for calls:


Element 1.3.8