Update issue templates

Author: jbunke

.github/ISSUE_TEMPLATE/api-type.md

@@ -0,0 +1,17 @@
+---
+name: API type
+about: For use by @jbunke only
+title: API MVP | `type`
+labels: api
+assignees: jbunke
+
+---
+
+## Description
+Implement AST nodes related to the `type` type needed for the MVP.
+
+## Properties
+* [ ] `prop_name`
+
+## Functions
+* [ ] `func_name`