Add animation for Billy on Login Screen

[lyqht]

Context

This animation will be shown on the login screen. Intended as a design delight, so it's on the lower priority now. But if you do create this, the many users that use Billy will see it while trying to sign up / login 😄

Tasks

It's up to you propose how Billy's animation will be like.

• For folks who want to try designing the animation, if you don't know how to code - no worries. feel free to just show the animation in any form you like as a comment below. Someone else (or me) can figure out how to do it later.
• For devs who want to work on this card to try out animation on react native, DO NOT IMPLEMENT BEFORE APPROVAL of an animation design.

Misc knowledge for devs

Libraries for animation

• There is the lottie package for relatively easier conversion of Adobe AfterEffect animations to native component animations — if the design is created using that.
• There is a react-native-svg-animations library for svg animations, but it seems unmaintained, so don't try that.