Show WAIT action message more clearly

[joffrey-bion]

When the player's move is prepared, or when there is no hand in this turn because another player has a special action (pick from discard pile, play last card, etc.), it might not be clear to the player that we're just waiting for others.

The message in the top-left might not be very visible.
Something should also be written on the prepared move or in place of the player's hand, depending on the case. For instance a loading spinner/wheel with a message.