[e.cash] Open Cashtab in a new tab when user clicks Create Wallet
Summary:
We should open Cashtab in a new tab and keep the landing page open when the user clicks "create wallet".
Add a new prop openInNewTab to the custom Button component so that Buttons may open links in a new tab. Implement for the "Create Wallet" button on the landing page above the fold.
Test Plan:
Preview, click "Create Wallet", confirm Cashtab opens in a new tab
Confirm the "get eCash" button navigates without opening a new tab (previous behavior)
Reviewers: #bitcoin_abc, Kronkmeister
Reviewed By: #bitcoin_abc, Kronkmeister
Differential Revision: https://reviews.bitcoinabc.org/D16589