[meta] Set up issue templates

[aspiers]

In order to encourage high quality submissions to this issue tracker, this repo needs one or more issue templates as shown in https://github.com/isaacs/github/community and mentioned in #1472. We already have one proposal in #792 but it needs some reworking.

[oprogramador]

@aspiers
could you propose an issue template here?

[aspiers]

Too busy at the moment, hopefully someone else can...