Fixed compiler warnings.

ServerConfiguration.cs

@@ -2,28 +2,28 @@ namespace HermesSocketServer
 {
     public class ServerConfiguration
     {
-        public string Environment;
-        public WebsocketServerConfiguration WebsocketServer;
-        public DatabaseConfiguration Database;
-        public TTSConfiguration Tts;
-        public string AdminPassword;
+        public required string Environment;
+        public required WebsocketServerConfiguration WebsocketServer;
+        public required DatabaseConfiguration Database;
+        public required TTSConfiguration Tts;
+        public string? AdminPassword;
     }
 
     public class WebsocketServerConfiguration
     {
-        public string Host;
-        public string Port;
+        public required string Host;
+        public required string Port;
     }
 
     public class DatabaseConfiguration
     {
-        public string ConnectionString;
+        public required string ConnectionString;
         public int SaveDelayInSeconds;
     }
 
     public class TTSConfiguration
     {
         public long OwnerId;
-        public string DefaultTtsVoice;
+        public required string DefaultTtsVoice;
     }
 }