This change shows STORJ token balance on the billing overview page instead of the Stripe balance it shows currently.
It changes the text on the "Available balance" card to reflect the new balance being displayed. Finally, it adds shortcuts to navigate straight to token history or add tokens modal when call to action on "Balance card"
Issue: https://github.com/storj/storj/issues/5204
Change-Id: Ic88e43c602e4949b6c6be4c7644c04f3c7d38585