Add issue templates

[RankoR]

No description provided.

[m4pl]

The forms look good overall. Could we add a required checkbox confirming that the reporter searched for existing issues to reduce duplicates? It would also be helpful to request the device model and build number, since the app version alone may not be enough to reproduce a problem. Do we want blank issues to be available to everyone, or should blank_issues_enabled be set to false so they remain available only to maintainers?

[RankoR]

@m4pl Not sure about a checkbox, I wanted to simplify the form as much as possible to not scare off a user.

As for the blank_issues_enabled - yes, ideally we shouldn't allow blank issues creation, but as I understand, setting it to false will also disable them for us (write access required to create them, we don't have it).