Implement Password Health Report

Introduce a password health check to the application that evaluates every entry in a database. Entries that fail  various tests are listed for user review and action. Also moves the statistics panel to the new Database -> Reports  widget. Recycled entries are excluded from the results.

We now have two classes, PasswordHealth to deal with a single password and HealthChecker to deal with all passwords of a database.

Tests include passwords that are expired, re-used, and weak.

* Closes #551

* Move zxcvbn usage to a centralized class (PasswordHealth)  and replace its usages across the application to ensure standardized interpretation of entropy calculations.

* Add new icons for the database reports view

* Updated the demo database to show off the reports

src/gui/DatabaseTabWidget.cpp

@@ -457,6 +457,11 @@ void DatabaseTabWidget::changeMasterKey()
     currentDatabaseWidget()->switchToMasterKeyChange();
 }
 
+void DatabaseTabWidget::changeReports()
+{
+    currentDatabaseWidget()->switchToReports();
+}
+
 void DatabaseTabWidget::changeDatabaseSettings()
 {
     currentDatabaseWidget()->switchToDatabaseSettings();