Add c-skeleton component set

[TylerAPfledderer]

Component set used to provide placeholder loading state of some component.

This is an alternative to some text, loading bar, spinner, etc. where the component itself is presented as a solid highlighter on load before the content is rendered.

Contains a set of components to define whether the content to be loaded is text, and avatar, solid block, etc.

See React Package Skeleton

Important

Depends on the composable usePrevious to isolate reference and change of state to the isLoaded prop. Consider building this composable first, or building a computed within the component. usePrevious is only used in this component and made available for other uses.