[Hotfix - TF Flux CD Automation] Use secrets to store each HelmRelease values file content

[v-ctiutiu]

Overview

Issue description:

• Each automation step from the Starter Kit is using a values file, to create each Flux CD HelmRelease.
• The HelmRelease manifest created via Flux CLI, embeds values file content in CLEAR TEXT (secrets as well)
• We ask the user to commit this file in Git - NOT OK to commit secrets! (WIP - the main project README was updated, to guide the user on creating private Git repositories for now)

Solution:

Create a Kubernetes generic secret for each values file content, and point each Flux CD HelmRelease to use the secret.

[v-ctiutiu]

Doesn't quite follow GitOps principles. Evaluating sealed-secrets, which Flux CD supports out of the box.