[RFE] enable environment from secrets through envVars implementation

[goshlanguage]

Current situation

Ranging over a key value pair for the extraEnvVar value is restrictive, and prevents setting the environment from secrets. It is not possible with this implementation to set an environment variable from a secret managed by an operator like the 1pass secrets operator or external-secrets, or what have you.

A common pattern for injecting secrets into environment can be seen in charts such as the external-dns bitnami chart. For example, this chart provides a stub called extraEnv in values.yaml:

## extraEnv:
## - name: VARNAME1
##   value: value1
## - name: VARNAME2
##   valueFrom:
##     secretKeyRef:
##       name: existing-secret
##       key: varname2-key
extraEnv: []

This is rolled up into the container spec env attribute here.

Adopting this pattern allows nebraska operators to use these secrets managers in conjunction with this chart, something that I don't see possible at current.

Impact

We have to maintain our own fork of this repo because we can't inject secrets as we do with most other projects

Ideal future situation

Please see my PR to enable this #514

**Implementation options

I'm open to feedback, please let me know if there's a more preferable way to bring these in

Additional information

[goshlanguage]

Closed by #514