Changes and new development compared to: https://issues.apache.org/jira/browse/HARMONY-5886
-BaseFormDialog: represents a base form dialog which will be used to query data of policy entries
-BaseFormDialog is used for KeystoreEntryEditFormDialog to inherit from, to create a form dialog to view and edit the keystore and the keystore password url entries.
-Edited policy file is displayed in a text field.
-Central check and confirmation for unsaved changes before certain operations (exit, open file, start new file).
-ListAndEditPanel which provides a listing and editing interface for various entities.
This will be used to list and to provide an entry point for editing grant entries, permissions, principals.
-The New menu works now
-GrantEntry and its parts (permissions, principals) are created.