Use GitHub organisation templates

[markusweigelt]

Clearer issue description and so fewer queries to the issue creator and communication overhead.

For example:
https://github.com/pods-framework/pods/issues/new/choose

[solth]

We do have a few issue templates for bug reports and feature requests now. Do we need more or does this cover most cases? I personally think we should limit the number of templates to a low number to not make the selection too confusing, but if there is need for one or two more templates that would still be well within such a limit.