Scaffold GH Issue + PR Templates

[justlevine]

Want to make sure these are done before our v0.1.0 release and call for feedback/contributions at Contributor Day.

Shouldn't be more than reappropriating templates from existing WordPress/* repos and tweaking some stuff.

[jeffpaul]

@karmatosed @neillmcshea do either of you want to take a stab at what these could/should be across all the AI repos (perhaps starting here and then we can replicate to the others)?

[karmatosed]

I will happily take this on.