Add filter for usernames + refresh button into multiplayer

[Eldenroot]

New multiplayer in 3.1 is a really huge step ahead. But there are some ideas:

• add a filter or search bar for usernames
• add a collum for a country
• add a refresh button
• host should hava rights to add AI opponent only, not connected users

one more thing - I get disconnection every time (note by farin fixed)