Option to set a type of mail to require interaction

[trviggo]

Create an option in the dropdown menu for mail where you currently have mark as read, add to notes and filter to make any mail of that kind require action before the game can continue. With this action being a small check mark in the bottom corner of the contents of the mail. 

This will enable us to never miss out on mail we wanna read, such as availability for reserve games, player concerns, international instructions etc. without hurting the default experience in any way. A massive QoL buff just in general, but also for the timeout feature. 

[Zachary Whyte]

Thank you for the suggestion, we'll put this under consideration.