htpasswd file generation using helm

[pshanoop]

I learned today, Since Helm v3.2.0, Helm support {{ htpasswd "user" "password" }}. So maybe we can add this to generate a configmap file for htpasswd plugin.

This means, we will break helm -v2 support. I don't if we passed that already 😄

Tomorrow, I will try this. I would like others opinion.

[pshanoop]

A PR is created. #69.