add command line option to set log level

src/main/java/com/sparrowwallet/sparrow/Args.java

@@ -2,6 +2,7 @@ package com.sparrowwallet.sparrow;
 
 import com.beust.jcommander.Parameter;
 import com.sparrowwallet.drongo.Network;
+import org.slf4j.event.Level;
 
 public class Args {
     @Parameter(names = { "--dir", "-d" }, description = "Path to Sparrow home folder")
@@ -10,6 +11,9 @@ public class Args {
     @Parameter(names = { "--network", "-n" }, description = "Network to use")
     public Network network;
 
+    @Parameter(names = { "--level", "-l" }, description = "Set log level")
+    public Level level;
+
     @Parameter(names = { "--help", "-h" }, description = "Show usage", help = true)
     public boolean help;
 }

src/main/java/com/sparrowwallet/sparrow/MainApp.java

@@ -1,6 +1,7 @@
 package com.sparrowwallet.sparrow;
 
 import com.beust.jcommander.JCommander;
+import com.sparrowwallet.drongo.Drongo;
 import com.sparrowwallet.drongo.Network;
 import com.sparrowwallet.drongo.wallet.Wallet;
 import com.sparrowwallet.sparrow.glyphfont.FontAwesome5;
@@ -119,6 +120,10 @@ public class MainApp extends Application {
             System.exit(0);
         }
 
+        if(args.level != null) {
+            Drongo.setRootLogLevel(args.level);
+        }
+
         if(args.dir != null) {
             System.setProperty(APP_HOME_PROPERTY, args.dir);
             getLogger().info("Using configured Sparrow home folder of " + args.dir);