Modified .vimrc and md template to match new markdown format

I started using Visual Studio Code for markdown notes and I'm trying to
keep the markdown files as agnostic as possible.  Vim will now match the
frontmatter style of VSC and (to an extent) Notable

.vim/templates/md

@@ -1,16 +1,17 @@
 :insert
+---
 
-# Title
-
-Created: 
-
-Updated: 
-
-## Summary
-
-
+tags: [ untagged ]
+title: 
+created: 
 
 ---
 
-## Reference(s):
+# Title
+
+## Summary
+
+___
+
+## Reference(s)