Add GitHub issue template (#873)

Author: chrnorm

.github/ISSUE_TEMPLATE/config.yml

@@ -0,0 +1,5 @@
+blank_issues_enabled: false
+contact_links:
+  - name: Features, Bug Reports, Questions
+    url: https://github.com/common-fate/granted/discussions/new/choose
+    about: Our preferred starting point if you have any questions or suggestions about configuration, features or behavior.

.github/ISSUE_TEMPLATE/preapproved.md

@@ -0,0 +1,9 @@
+---
+name: Pre-Discussed and Approved Topics
+about: |-
+  Only for topics already discussed and approved in the GitHub Discussions section.
+---
+
+**DO NOT OPEN A NEW ISSUE. PLEASE USE THE DISCUSSIONS SECTION.**
+
+**I DIDN'T READ THE ABOVE LINE. PLEASE CLOSE THIS ISSUE.**