Add status field to online players

[MikhailDeriabin]

General description

Online players should also have a status field, which is an enum, representing what players is doing or where he / she is. The enum have the following values:

• UI
• BattleWait
• Battle

Things to notice

The default value should be set to UI

Tasks

• Add body with field status to /online-players/ping POST endpoint
• Make status field to be returned from the /online-players GET endpoint