Adding John Muchovej's Devcontainer Templates (devcontainers#170)

* Adding John Muchovej's Devcontainer Features/Templates

* Remove `../features` until published.

Author: jmuchovej

_data/collection-index.yml

@@ -328,3 +328,7 @@
   contact: https://github.com/JasonTheDeveloper/features/issues
   repository: https://github.com/JasonTheDeveloper/features
   ociReference: ghcr.io/jasonthedeveloper/features
+- name: Templates by John Muchovej
+  maintainer: John Muchovej
+  contact: https://github.com/jmuchovej/devcontainers
+  ociReference: ghcr.io/jmuchovej/templates