Fix up chart linting, add docs and lint script (#146)

This updates the Helm linting system with the following changes:

- Import lintconf.yaml with small change to comment distance in order to
match existing values.yaml standards
- Update Chart.yaml and values.yaml in each chart to pass linting
standards
- Maintainers added to each chart from OWNERS + CODEOWNERS, the linter
requires GitHub usernames so argo-events maintainer names were converted
- README updated with documentation around chart standards and testing
- A local shell script added for running lint tests locally

charts/argo/Chart.yaml

@@ -2,5 +2,11 @@ apiVersion: v1
 appVersion: "v2.4.2"
 description: A Helm chart for Argo Workflows
 name: argo
-version: 0.6.2
+version: 0.6.3
 icon: https://raw.githubusercontent.com/argoproj/argo/master/argo.png
+home: https://github.com/argoproj/argo-helm
+maintainers:
+  - name: alexec
+  - name: alexmt
+  - name: jessesuen
+  - name: benjaminws