Issue #3182022 by karengrey, rszrama: Link to free resources for U.S. sales tax calculation

Following Ryan's recommendation to use the markup used for System Status, the simplest way to inject this to the TaxTypeListBuilder was to add additional markup to the render() function.

The markup has been added to a separate file so the TaxTypeListBuilder::render function stays looking clean.

There are conditions added so the markup is only added if there are any stores with an US or CA address.

I have also added a statement to check if commerce_avatax is enabled, which changes the text in the right column to a thank you message and a link to the AvaTax login. This text is to be finalised by Ryan/Summer Baker

A new Library has been added for a new CSS file and an images folder added with two svg files for each column. The Sales Tax Risk Assessment is interactive, it would be ideal to change this svg to be static (I couldn't scale the JPG provided in the issue without losing a fair amount of quality)