Add ImportTool option for creating LOTR: Rise to War dataset from a workbook

[tbm0115]

Similar to creating the workbook (#32), there needs to be an administrative tool around reading the contents of the workbook and transposing the contents into the JSON files required for the site.

• Add ImportTool view/option for selecting a workbook and transposing the contents to JSON files
• Add documentation on how to go through the dataset update process