Create issue template

[JayFoxRox]

There should be a template for creating issues:

A log of the games output is necessary and the issue template should ask for it.
It should ask for the used cmake command line, installed dependency versions, used git revision, used game version (which CD / gog.com hotfix number + how did you install it), used compilers, platform and possibly even a tree of the game folder.
It should also ask for screenshots for graphical issues.

It should also tell people to use our gitter channel for questions and support requests.

There's probably more I'm forgetting.