Feature: add StatefulSet templates

[GRomR1]

Hi all

I would like add this two useful features

• extract a Pod spec from Deployment to _pod.tpl file (don't change anything inside except indenting)
• add a capability to create StatefulSet based on this tpl

Inspired by this chart.

Also the common sample with name web-app.values.yml is great but is complex to understand a base idea and run a simple test. I add a new two examples that easy to run.

[GRomR1]

@randreev1321 could you pls review this PR?

[randreev1321]

Hi @GRomR1.

Thanks for your activity and suggestion. Looks wery nice!

Could you add the usage of the pod template for other workloads as well?

[randreev1321]

Think it'll be better to finish this PR before #32

[GRomR1]

@randreev1321

• I've add this definition to cronjob, job, helm-hooks. any other places?
• agree with you, merge this before #21 - add enableAffinity flag #32

helm-hooks and job I can't test, cron-job tested with this command:

❯ helm template whoami \
  --values ./samples/cron-jobs.values.yml  \
  ./ | k apply -f - --dry-run=client
cronjob.batch/whoami-flush-cache created (dry run)
cronjob.batch/whoami-mailing created (dry run)
cronjob.batch/whoami-report created (dry run)

[rantanevich]

By the way, you can also define helpers.container template and use it to declare containers and initContainers in your helpers.pod.