github: replace discord with GitHub discussions

Signed-off-by: Paul Meyer <49727155+katexochen@users.noreply.github.com>

.github/ISSUE_TEMPLATE/config.yml

@@ -1,5 +1,5 @@
 blank_issues_enabled: true
 contact_links:
-  - name: Confidential Computing Discord
-    url: https://discord.com/invite/rH8QTH56JN
-    about: Join the Confidential Computing community!
+  - name: Having trouble or questions?
+    url: https://github.com/edgelesssys/constellation/discussions/new?category=q-a
+    about: Open a discussion instead! We will be happy to help you.

.github/ISSUE_TEMPLATE/question.md

@@ -1,14 +0,0 @@
----
-name: Question
-about: Get help or more information on a topic
-title: ''
-labels: question
-assignees: ''
-
----
-
-<!--
-Ask your question here.
-Make sure you've checked the docs at https://docs.edgeless.systems/constellation
-You can also search within the existing issues at https://github.com/edgelesssys/constellation/issues
--->