Add basic issue template configuration

This allows us to enable GitHub Issues for the migration from Redmine.
And we don't even have to worry about users filing new bug reports on
GitHub because it's simply not possible (yet).

.github/ISSUE_TEMPLATE/config.yml

@@ -0,0 +1,8 @@
+blank_issues_enabled: false
+contact_links:
+  - name: Audacious Community Support
+    url: https://github.com/orgs/audacious-media-player/discussions
+    about: Please post here for help, general feedback, or ideas.
+  - name: Redmine Migration Status
+    url: https://github.com/orgs/audacious-media-player/discussions/125
+    about: See the current status of our bug tracker migration.