Currently, in order to avoid creating another assembly (DLL) that needs to be including with installs, we effectively copy the contents of the shared Common/ project into every other mod project that needs it. That way. there is no Common.UI.dll, and the necessary types are embedded as resources.

However, this approach stops Common/UI from being used as true library. Access modifiers are set based on the fact that Common/* files are considered internal to other projects (because the comon files are effectively copy/pasted in) and don't truly reflect correct library access levels. Additionally, builds take longer and there is a greater risk of namespace conflicts.

Instead, we ought to:

1. Reference the Common project from other mod projects. At runtime, the Common assembly then needs to exist. We have a choice of either publishing a Common.UI.dll assembly that all must download, or simply stitch it to the resulting mod DLL file. The latter would be better.
2. Separate the monolithic Common project into minilibraries. At the moment, there is only one, so renaming to Common.UI will suffice.
3. To accomplish the last part of the first (1.) point, we need to clean up the referenced assemblies each mod relies on, and stitch all dependent libs into the single resulting mod assembly (DLL).