Implement guide for new issues

[grabbou]

With details how issue should look like, what kind of snippets should be included and in which cases plunkr is needed. There are lots of abandoned issues with no details provided that looks like typical REST setup problems that unfortunately need to be closed due to lack of informations that would've helped us to solve them.

[daviesgeek]

I'm going to work on this, since I've seen scores of issues that needed more information/examples provided.