Pre-fill new issue with template

[dialex]

trafficstars

By convention, GitHub will look for an issue_template.md file to pre-fill the new issue page. Right now, the user gets an empty page and has to read PR/Contributing guidelines in at least two files.

With this PR, those instructions can be moved to a template that is displayed automatically to every user that creates an issue.

Limitations: I don't have enough context to make sure the templates are 100% aligned with your workflow, but at least it's a starting point for your team to later customise ;)

[gep13]

@dialex in order to be able to merge this PR (although some work may be required to complete it) I am going to need you to sign the CLA. Is this something that you would be in a position to do? Thanks!

[dialex]

~~Sure thing, how do I do it?~~ Done 😉

[CLAassistant]

All committers have signed the CLA.

[dialex]

I think it's all done from my side @gep13