Expose colorPalette directly to the lineplot vis

[VinzentRisch]

Add the ability to specify the default colorPalette as a param to assist with clarity in paired color palette plots.
I have a plot that needs the color pallette category20 because the data is paired. I want to be able to set the color palette outside in the pipeline calling the visualizer so the user sees the intended plot directly.

[lizgehret]

Adding comment for myself for clarity:

• add the ability to specify the default colorPalette as a param to assist with clarity in paired color palette plots