[Cashtab] toggle display between tx history and tokens

Summary: Create custom tab pane components to display either TX history or tokens depending on user selection. Hide scroll bars (but do not disable scroll functionality) to prevent content jumping.

Test Plan: npm start ; toggle between "Transaction History" and "Tokens", observe smooth transition, orange line lines up with active label.

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Subscribers: Fabien

Differential Revision: https://reviews.bitcoinabc.org/D9344