DMN Properties panel - UX enhancements

1. Increase the size of the Description input to a text field.
2. Combine the three current style related menus (Background details, Font settings, Dimensions) into a single menu.

Notes re: Styles section:

• As the context of these items is very different from the other properties, it might be beneficial to the user to group them together thereby distinguishing them from the rest.
• The extra menu headers required for these additional menus takes up valuable screen real estate, that could otherwise be used by higher priority properties.
• If the user does want to use the style settings, we're creating additional work to make them both scroll down and open the additional related menus.