#358 Start refactoring PasswordSecurity

- Add new methods temporarily to NewEncrMethod interface
   - No data source access within EncryptionMethod implementations
   - Generate the salt within the EncryptionMethod implementation
- Deprecate static methods on PasswordSecurity
- Adjust AbstractEncryptionMethodTest to test the classes with the new interface
- Add getter for data source instead of accessing field directly

src/main/java/fr/xephi/authme/command/CommandService.java

@@ -88,8 +88,7 @@ public class CommandService {
      * @return The used data source
      */
     public DataSource getDataSource() {
-        // TODO ljacqu 20151222: Add getter for .database and rename the field to dataSource
-        return authMe.database;
+        return authMe.getDataSource();
     }
 
     /**