feat: refactor avatar creator scene (#289)

## [SDK-968](https://ready-player-me.atlassian.net/browse/SDK-968)

## Description

- Refactor avatar creator elements scene and separate avatar management
from simple avatar creator script

[SDK-968]:
https://ready-player-me.atlassian.net/browse/SDK-968?atlOrigin=eyJpIjoiNWRkNTljNzYxNjVmNDY3MDlhMDU5Y2ZhYzA5YTRkZjUiLCJwIjoiZ2l0aHViLWNvbS1KU1cifQ

Author: rk132