Update issue templates

Warn people that this is not the place to post issues.

.github/ISSUE_TEMPLATE/all-issues.md

@@ -0,0 +1,17 @@
+---
+name: All issues
+about: Warning template
+title: ISSUES POSTED TO GITHUB WILL BE IGNORED
+labels: wont fix
+assignees: ''
+
+---
+
+ALL ISSUES POSTED HERE WILL BE IGNORED.
+
+Autoware has moved from GitHub to [GitLab](https://gitlab.com/autowarefoundation/autoware.ai). Please post your issue to one of the GitLab issue trackers.
+
+IF YOU POST AN ISSUE HERE, NO ONE WILL ANSWER IT.
+
+IF YOU ARE MAKING A SUPPORT REQUEST, DO NOT POST AN ISSUE.
+Follow the [support guidelines](https://gitlab.com/autowarefoundation/autoware.ai/autoware/wikis/Support-guidelines) and ask your question at [ROS Answers](https://answers.ros.org/questions/ask/?tags=autoware).