Allow usage of built-in Layers outside of Timeline

[vedmakk]

Currently there is a dependency with the timelines theme provider that causes built-in layers that depend on the theme (like Interaction) to break when they are used outside of the react-svg-timeline (e.g. in a nivo component).

See usage of "useCursorStyle()" or "useZoomRangeStyle()" in MouseCursor.tsx.