webcomponent: Slot support without shadowdom

create a Slots API for webcomponent that doesn't need ShadowDom

slots are just elements created at one place that is moved to another. If a webcomponent is using slots without shadowdom we can look for the elements and move them. If the slots have data binding then this will be more of a problem but that should be fine if we keep the data-name

The issue names no files, tests, or entry points; start by locating the TypeScript webcomponent implementation and any existing slot handling. Define support for moving slot elements without Shadow DOM, including the stated data-name constraint for data binding, then add coverage showing the resulting slots work.

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