Improve "Open Kuberbetes YAML file" to avoid accidental opens and duplicate files

[datho7561]

From @vrubezhny :

When having a pod running, if you click on it's tree item once it opens its yaml file... Do you think it's a good thing?
I really don't like it as it opens this file in a new editor every time I eventually click on such a tree item...
Why don't we:

1. open it by double click (instead of single click)?
2. reuse the same editor for it? (probably it's difficult, but I believe it's possible)

[datho7561]

I think that 1. might not be possible, but 2. is possible.

I think we might rely on vscode-kubernetes to provide this functionality. If so, we should also rewrite the code so that we don't depend on vscode-kubernetes.

[vrubezhny]

I just checked - the opening a Deployment YAML by single click is following the VSCode preferences:

... so users are able to configure VSCode to use single or double click to open a tree node (Deployment YAML in our case). As such no any fix is needed for №1.