Add features entry for https://github.com/ksachdeva/devcontainer-features (#613)

Currently has features for nats-server, nats-top and natscli

Co-authored-by: Álvaro Rausell Guiard <33221237+AlvaroRausell@users.noreply.github.com>

Author: ksachdeva

_data/collection-index.yml

@@ -1230,6 +1230,11 @@
   contact: https://github.com/navinkrishnan/devcontainer-templates-btp/issues
   repository: https://github.com/navinkrishnan/devcontainer-templates-btp
   ociReference: ghcr.io/navinkrishnan/devcontainer-templates-btp
+- name: Features by ksachdeva
+  maintainer: Kapil Sachdeva
+  contact: https://github.com/ksachdeva/devcontainer-features/issues
+  repository: https://github.com/ksachdeva/devcontainer-features
+  ociReference: ghcr.io/ksachdeva/devcontainer-features
 - name: Gemini CLI (via npm)
   maintainer: siri404
   contact: https://github.com/siri404/devcontainer-ai-features/issues