Upgraded to RN 0.53, VN 0.17, icons & bug fixes

[carloskelly13]

• [x] Upgraded icons with new Victory logo with TM
• [x] Upgraded back to React Native 0.53 and Victory Native 0.17
• [x] Fixed minor visual glitches
• [x] Added new XIB-based launch screen for iOS
• [x] Fixed production builds