TypeScript: Convert `elements` and `element-library` packages

[swissspidy]

Task Description

The two element packages must be converted to TypeScript.

The types for the specific elements as well as for general elements (and classes of elements, such as media elements) should be moved from the types package to the relevant package and refined once here.

At the same time, other types will move to where they belong and correctly referenced:

• resource types will be moved to the media package
• pattern types will be moved to the patterns package

All references to the types should be updated.