Include IStandardRenderingParametersItem in Synthesis

[emf-bgadd]

When code generation occurs on an item which is derived from sitecore Standard Rendering Parameters template, that template's generated code should implement a built-in interface for IStandardRenderingParametersItem.

Currently, synthesis will create this item in the first project that requires it and point all other solution projects with templates that derive from IStandardRenderingParametersItem to that project (if auto friending is enabled).