[Cashtab] Webpack upgrade, part 5
Summary:
T1682
Remove all the default create react code files that will not be used after the Cashtab codebase is dropped into this updated version of create-react-app.
Test Plan:
The app should not work anymore.
Review T1682 to understand the context of this step. We'll do a feature freeze after the Airdrop diff and get to a working upgrade, deprecating the old create-react-app Cashtab.
Reviewers: #bitcoin_abc, kieran709
Reviewed By: #bitcoin_abc, kieran709
Differential Revision: https://reviews.bitcoinabc.org/D11233