Parabeac Themes should generate an Asset Sheet

[siliconivan]

When leveraging assets that are being generated from Parabeac, you're often leveraging an SVG Object or Image which requires a String as the call. For example: "assets/home_icon".

I believe this could be reduced to something like ProjectAssets.home_icon which would return the SVG already prepared as a widget. This would reduce the amount of code that the developer would have to write when leveraging the assets.