Convert ProductResolver to kotlin and make it possible to use it without a chooser

The show() method was deprecated and replaced by resolve() since it is possible now to use the resolver without visible interaction.

Author: rekire

sample/src/main/java/io/snabble/testapp/BaseActivity.java

@@ -78,7 +78,7 @@ public boolean dispatchKeyEvent(KeyEvent event) {
             new ProductResolver.Builder(this)
                     .setCodes(ScannedCode.parse(SnabbleUI.getProject(), code))
                     .create()
-                    .show();
+                    .resolve();
 
             return true;
         }