[CashTab] Add Fbt dependencies, init script and intl to App component

Summary: See title.

Test Plan: npm install & npm start. Followed by npm run test.

Reviewers: O1 Bitcoin ABC, #bitcoin_abc, josephroyking, deadalnix

Reviewed By: O1 Bitcoin ABC, #bitcoin_abc, josephroyking, deadalnix

Subscribers: deadalnix

Differential Revision: https://reviews.bitcoinabc.org/D8559