Improve performances of users list

[srosset81]

On old mobiles, when we have more than 100 users, it becomes slow to scroll through users (also when we want to share an event)

This is probably related to the fact images are too big.

But using https://github.com/bvaughn/react-window could help as well.

[srosset81]

Done 476cd67

[srosset81]

I had to revert the commit because we cannot use useState within rows when using react-window. When we toggled on an invitation, it didn't appear toggled on.

I will have to keep the state of clicked contacts one level higher. (https://stackoverflow.com/questions/72405479/react-window-rows-call-usestate)

But since I don't want this to enter into conflict with #22, I will wait for @andreipopa-who to finish his PR.