Create issue templates

[J0B10]

From my experiences issue templates really improve the quality of bugreports and feature requests.

We could also use them to give our todos a uniform layout.

[derNiklaas]

Maybe even add all of those templates.
https://github.com/codeoverflow-org/chatoverflow/community

[J0B10]

I don't really like the ones form Github. They are way to generic.
And I don't really see a need for a Code of Conduct or a Contributing guideline.

[sebinside]

If you are experienced, you're welcome to add a template! (I'm a noob, lol)