adds StrongBox detection via PackageManager class

app/src/main/java/com/besendorf/androidsecurityscanner/MainActivity.java

@@ -141,6 +141,7 @@ public class MainActivity extends AppCompatActivity {
             json.put("ro.boot.veritymode", getProp("ro.boot.veritymode")); //unklar
             json.put("KeyStore", keyStorePresence());
             json.put("Strongbox", isStrongbox());
+            json.put("StrongboxPM", isStrongboxPM());
             json.put("FingerprintQuality", biometricQuality());
             json.put("DRM", drmInfo());
         } catch (JSONException e) {
@@ -156,6 +157,11 @@ public class MainActivity extends AppCompatActivity {
 
     }
 
+    private boolean isStrongboxPM() {
+        return this.getPackageManager()
+                .hasSystemFeature(PackageManager.FEATURE_STRONGBOX_KEYSTORE);
+    }
+
 
     private boolean fingerprint() {
         //FingerprintManager needs Android 6.0