[bitnami/mongodb] Add ability to configure SA for backup

[mkuendig]

Description of the change

This MR will add the possiblity to change the ServiceAccountName in the mongoDB backup that the bitnami chart can create. We use Hashicorp vault with init containers and we need to fetch the credentials via a predefined service Account.

If the ServiceAccount is changed, it needs to pre-exist, or the job won't run. No error is thrown if the SA does not exist.

Benefits

For enterprise environments where the SA needs to be customized or an existing one that needs to be used can be used.

Possible drawbacks

None known.

Applicable issues

• fixes MongoDB Chart, Backup allow ServiceAccount to be configurable #33039

Additional information

Checklist

• Chart version bumped in Chart.yaml according to semver. This is not necessary when the changes only affect README.md files.
• Variables are documented in the values.yaml and added to the README.md using readme-generator-for-helm
• Title of the pull request follows this pattern [bitnami/<name_of_the_chart>] Descriptive title
• All commits signed off and in agreement of Developer Certificate of Origin (DCO)

[gongomgra]

Thanks for your contribution!

[gongomgra]

Can you please rebase your branch with main and update the PR?

[mkuendig]

Can you please rebase your branch with main and update the PR?

@gongomgra Hi, I have tried to rebase this, but have now heaps of changes. I'm not sure if this is what you want. If not, I need help. I'm no dev and have a hard time to get this right with such a large repo.

[gongomgra]

Hi @mkuendig

I think this guide would be of help. Just remember that our principal branch is named main (you need to rebase your add_mongodb_backup_serviceaccount branch with that), and that you need to push your custom branch afterwards

https://gist.github.com/ravibhure/a7e0918ff4937c9ea1c456698dcd58aa

Hope it helps!

[mkuendig]

@gongomgra Thanks a ton for the guide. I think I could do it correctly now. Can you pls check.