Add animated send progress bar, update modals and add page transitions animations

[cvarley100]

Description

Page flow and action-oriented animations will make the mobile app feel smoother and more satisfying.

This PR will add:

• Improved send progress bar and slider
• Modal UI update
• Page transition animations

See #458

Type of change

• Enhancement

How Has This Been Tested?

Tested across Android/iOS.

Checklist:

• My code follows the style guidelines for this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• New and existing unit tests pass locally with my changes
• For changes to mobile that include native code (including React Native modules): I have verified that both iOS and Android successfully build in both Debug and Release modes