chore: Create support_request template

Creating a new "support request" template to direct users who have support needs away from creating a new issue.

.github/ISSUE_TEMPLATE/support_request.md

@@ -0,0 +1,11 @@
+---
+name: Support request
+about: Get help troubleshooting an issue
+title: ''
+labels: 'customer support'
+assignees: ''
+
+---
+The issue tracker is not for support requests. 
+
+If you would like support with Outline Manager or Outline Client, please review the help articles on [support.getoutline.org](https://support.getoutline.org/), and [contact us](https://support.getoutline.org/s/contactsupport) if you need further assistance. Developers, please post your questions on the SDK [Discussion board](https://github.com/Jigsaw-Code/outline-sdk/discussions).