ExtraEnv support for all controller deployments

[bpinske]

What this PR does / why we need it:

Support passing in extraEnv variables to helmController, notificationController, kustomizationController, sourceController

Which issue this PR fixes

• fixes #146

Checklist

• [x] DCO signed
• [x] Chart Version bumped
• [x] helm-docs are updated
• [x] Helm chart is tested
• [x] Update artifacthub.io/changes in Chart.yaml
• [x] Run make reviewable

[ravilr]

This has been addressed in https://github.com/fluxcd-community/helm-charts/pull/179.

/close