skaffold.yaml doc needs to be more readable.

### Actual behavior
Since `skaffold.yaml` is a very big file when listing all the possible keys with descriptions along side, it is very difficult to follow along which key is the child of which key, or what other keys there are as an option under a parent key.

### Expected behavior
To make it more easy to navigate in the documentation page, each parent key should be made into a drop down or accordion UI, so that we can collapse the keys(and child keys) which are not required and expand only those parent keys which we need to lookup.

### Steps to reproduce the behavior
1. Go to the `skaffold.yaml` page in the skaffold documentations.

If this suggestion seems right, i can work on it.