Move most of the examples in etc/ to kernel_gateway_demos

[jupyter-server]

Move most of the examples in etc/ to kernel_gateway_demos

[parente]

Should we move the rest of the api_examples too? Was that a miss?

[poplav]

My concern was the api_examples were being used at the running section. Where the running section is the baseline example usage of the repository and the complete set of demos were linked below. We could duplicate them in both repositories, I am just not sure if we would want to completely remove all even basic examples?

[parente]

Ah, I see it now. Let's get the scotch one out of here so we don't have to maintain it in two place and update the README not to refer to that one. But the other simple ones can stay for the reason you gave.