feat(secret): support env from secret

[oziey88]

getting an env from secret is useful when we want to add another ENV without adding additional ENV on the deployment manifest. yet we can also use externalsecret to generate the secret from another secret provider

[pmint93]

@oziey88 I have wanted to move all environment variables to secret (or configmap) but don't have the chance to do it yet. It would be amazing if you (or anyone) can make me a favor by doing that.

In case you just want to focus on this PR only, I suggest you use the field named envFrom: [] instead of secret: {} to prevent confusing

Last but not least, don't forget to bump the chart version in Chart.yaml

[oziey88]

Hi @pmint93
Thank you for the feedback. will update the variable key and chart version.

IMHO,
not all environment variables are necessarily moved to secret, what we already have in this chart is good enough.
like SSL and database, it's easy to understand when we have a dedicated section for it on the values.yaml.

my PR is meant to cover the credentials, hence we are not putting it on values.yaml