[native] Introduce ConnectEthereum screen
Summary:
For now it's going to look rather messy. In subsequent diffs I will:
- Fix up the styling and spacing of the buttons
- Replace the text with an ordered list
- Introduce the Ethereum icon from the designs
Depends on D7725
Test Plan:
Reviewers: atul, ginsu
Reviewed By: atul
Subscribers: tomek
Differential Revision: https://phab.comm.dev/D7729