[Front End] - Integrate webgl-globe planet with previous planet

[syt123450]

As a developer, I want to integrate the earth built by webgl-globe with our previous earth demo, so that we can easily render different earth in our project.

Definition of done: Create a demo render different earth.

[syt123450]

I will write a demo to show how to switch between our earth and google earth.

[syt123450]

I add a demo to show how to switch between our own earth and google's earth, the demo will show will our own earth first, and 5 seconds later, will switch to google's earth, and 5 seconds later, the scene will switch back to our own earth.