Add an issue template to reduce confusion

Plenty of issues are opened on this repository by people mistaking this
for the main Django issue tracker. Maybe some default text in the issue
template, complete with documentation links, can help some of them.

Author: rixx

.github/issue_template.md

@@ -0,0 +1,13 @@
+---
+name: Issue
+about: Submit a bug report or feature request for the website djangoproject.com
+
+---
+
+This is the issue tracker for the website at djangoproject.com, **not** for Django itself.
+
+If you are looking for help or support with using Django, please follow the links in [our documentation](https://docs.djangoproject.com/en/dev/faq/help/).
+
+If you want to submit a bug report or a feature request to Django, you can find instructions [here](https://docs.djangoproject.com/en/dev/internals/contributing/bugs-and-features/).
+
+If you want to [report a bug on translations](https://docs.djangoproject.com/en/stable/internals/contributing/localizing/#translations) in Django or djangoproject.com, please use [Transifex](https://www.transifex.com/django/django/dashboard/).