Add a setting on import, to read a Task Template.

If a new Site Progress Item (or any other object with tasks) is created via the import, a list of predefined Tasks from the provided Task Template will also be created.

Limitation comment: If the Site Progress Item already exists, the import will not create Tasks- It is difficult to check if specific tasks from a specific task template have already been created or not. And we should avoid creating duplicate Tasks when importing the same file multiple times.