Add includeCRDs Field to HelmChart

This commit adds functionality for a user to specify that `helm` should
include CRDs when inflating a Helm Chart.

As of Helm v3, the `install-crd` hook is no more, with
`CustomResourceDefinitions` existing in the root of the chart, under the
`crds` directory.

When calling `helm template`, `helm` does not output these CRDs unless
the user passes the `--include-crds` flag to the command.

With this commit, users can set `includeCRDs: true` as part of their helm
chart definition in `kustomize.yaml` to have these included as part of
the output.

Signed-off-by: Devon Mizelle <devon.mizelle@onepeloton.com>

examples/chart.md

@@ -88,6 +88,7 @@ Define this base the usual way by creating a
 cat <<'EOF' >$DEMO_HOME/base/kustomization.yaml
 helmCharts:
 - name: minecraft
+  includeCRDs: false
   valuesInline:
     minecraftServer:
       eula: true
@@ -105,6 +106,10 @@ field, specifying a single chart.
 
 The `valuesInline` field overrides some native chart values.
 
+The `includeCRDs` field instructs Helm to generate 
+`CustomResourceDefinitions`. 
+See the [Helm docs for further info](https://helm.sh/docs/chart_best_practices/custom_resource_definitions/)
+
 Check the directory layout:
 
 <!-- @tree -->