Keep extra fields in template configurations after processing the template

[AmoebeLabs]

The Problem To Be Solved

Currently, a template replaces the full definition of the field. That is how it should work.

However, in some cases, and currently with the implementation of palettes for toolsets, the palette definition is removed if the toolset is a template.

This issue requests the template engine to keep existing fields to be maintained after the template is processed.

Additional background:

Related Issues (if any)

See:

• Add support for theming, palettes and swatches #218

(Optional): Suggested Solution

(Optional): Alternative Solutions