I.e. removed the sponge icon with some star dust and added a refactoring icon.
Also the templates has been streamlined wrt/ to questions, and a
"free form" template has been added, without structure.
* Adds Github issue and pull request templates
We might need to add few labels for knative/client repo as mentioned
in the template.
* Adds nightly build reference and swap client and serving section
* Asks user to paste output of kn version in bug report template
Daniel Helfand