Export storefrontPath from src/routes.ts

[tniezg]

Is your feature request related to a problem? Please describe.

When extending Client with extra endpoints, it's useful to have the standard path for APIv2 requests and routes to existing endpoints already provided by the SDK.

Describe the solution you'd like.

Export routes.ts values.

Describe alternatives you've considered.

-

Additional context

-

[tniezg]

#133