Add template

.github/ISSUE_TEMPLATE/plain.yml

+name: Miscellaneous
+description: A plain template for issues which do not fall into other categories.
+title: "MISC: <Please write a comprehensive title here>"
+
+body:
+- type: textarea
+  attributes:
+    description: >
+      Please describe the purpose of filing this issue
+  validations:
+    required: true