Remove njs-modules configmap (#959)

Problem: PR #934 did not remove the njs-modules ConfigMap 
and they are some lingering references to it.

Solution: Remove the njs modules ConfigMap and remove references.

Author: kate-osborn

.yamllint.yaml

@@ -30,7 +30,6 @@ rules:
     check-multi-line-strings: true
     ignore: |
       deploy/manifests/nginx-gateway.yaml
-      deploy/manifests/njs-modules.yaml
   key-duplicates: enable
   key-ordering: disable
   line-length:

deploy/manifests/njs-modules.yaml

@@ -111,10 +111,3 @@ This project uses [prettier](https://prettier.io/) to lint and format the JavaSc
 ```shell
 npm run format
 ```
-
-## Generate the ConfigMap yaml
-
-The NJS modules are mounted to the NGINX container using a ConfigMap. Once you have completed your code changes, ensure
-the [njs-modules.yaml](/deploy/manifests/njs-modules.yaml) and
-[NJS ConfigMap Helm template](/deploy/helm-chart/templates/njs-modules.yaml) are updated to reflect the new code. See
-[Update NJS module ConfigMaps](/docs/developer/quickstart.md#update-njs-module-configmaps).