[Community Tutorials] Add notebook with instructions and template for authoring community tutorials in Colab.
[Community Tutorials] Add notebook with instructions and template for authoring community tutorials in Colab.

PiperOrigin-RevId: 295237078

google/earthengine-community,google/earthengine-community,googleinterns/earthengine-community,google/earthengine-community,googleinterns/earthengine-community,googleinterns/earthengine-community