fix(helm): Drop bitnami repo reference

[kiblik]

As we are not using bitnami anymore, adding it as Helm repo is not needed.

[kiblik]

There is still one reference in the Helm README, but it is referring to a different use case (test of external DB)

django-DefectDojo/readme-docs/KUBERNETES.md

Lines 408 to 416 in 52ef305

	#### Step 2.5: Install PostgreSQL (Optional)
	If you need to simulate a PostgreSQL database external to DefectDojo, you can install PostgreSQL using the following Helm command:
	```bash
	helm repo add bitnami https://charts.bitnami.com/bitnami
	helm repo update
	helm install defectdojo-postgresql bitnami/postgresql -n defectdojo -f postgresql/values.yaml
	```

And two references in values.yaml, but there is no better replacement for documentation at the moment.

django-DefectDojo/helm/defectdojo/values.yaml

Line 392 in d41ceaf

# For more advance options check the bitnami chart documentation: https://github.com/bitnami/charts/tree/main/bitnami/postgresql

django-DefectDojo/helm/defectdojo/values.yaml

Line 464 in d41ceaf

# For more advance options check the bitnami chart documentation: https://github.com/bitnami/charts/tree/main/bitnami/redis

[valentijnscholten]

Should we mention somewhere that we have vendored the bitnami charts for now?

[kiblik]

Should we mention somewhere that we have vendored the bitnami charts for now?

Not sure if it is needed. How do you see it, @rossops?