Confirm screen mini-epic

[danjm]

All of these should be resolves as part of (or subsequent to) the confirm screen refactor:

• Refactor Confirm components Refactor Confirm components #3824
• NewUI: Indicate loading when confirmation screen is starting up NewUI: Indicate loading when confirmation screen is starting up #4195
• NewUI - Make gas price editable on confirm tx screen NewUI - Make gas price editable on confirm tx screen #3202
• [Beta] ERC20 approve() -- UI makes it look like tokens are being sent [Beta] ERC20 approve() -- UI makes it look like tokens are being sent #3423
• Keep confirm screen in background, when retry-dropped popup modal shows, until the modal is closed Dan F pointed out that not having it in the background more closely matches what is actually happening
• Design / UX updates as per the May 24, 2018 design sync Action Screens for Fishing Attacks Design#18