#1141 Add TOTP key field to database and PlayerAuth

- Add new field for storing TOTP key
- Implement data source methods for manipulation of its value

src/main/java/fr/xephi/authme/datasource/CacheDataSource.java

@@ -268,6 +268,15 @@ public class CacheDataSource implements DataSource {
         return source.getRecentlyLoggedInPlayers();
     }
 
+    @Override
+    public boolean setTotpKey(String user, String totpKey) {
+        boolean result = source.setTotpKey(user, totpKey);
+        if (result) {
+            cachedAuths.refresh(user);
+        }
+        return result;
+    }
+
     @Override
     public void invalidateCache(String playerName) {
         cachedAuths.invalidate(playerName);