CI: Disable blank issues, add links to QA discussions & show and tell (#16275)

Update the issue template

.github/ISSUE_TEMPLATE/config.yml

@@ -1,9 +1,12 @@
-blank_issues_enabled: true
+blank_issues_enabled: false
 version: 2.1
 contact_links:
   - name: 🤔 Question or Problem
     about: Ask a question or ask about a problem in GitHub Discussions.
-    url: https://github.com/langchain-ai/langchain/discussions
+    url: https://www.github.com/langchain-ai/langchain/discussions/categories/q-a
   - name: Discord
     url: https://discord.gg/6adMQxSpJS
     about: General community discussions
+  - name: Show and tell
+    about: Show what you built with LangChain
+    url: https://www.github.com/langchain-ai/langchain/discussions/categories/show-and-tell