Cleanup UI

[UnderratedDev]

UI needs some cleanup, the text for the login is not good and the logo is not relevant, etc.

[UnderratedDev]

https://reactnavigation.org/
https://docs.nativebase.io/
https://github.com/react-native-training/react-native-elements
Use these to make the ui nicer, especially the container, form, and content tags.

[UnderratedDev]

Use these icons from native-base to add images : https://docs.nativebase.io/Components.html#icon-def-headref