[bitnami/mongodb] add emptyDir sizeLimit

[monotek]

Description of the change

add a configurable sizeLimit to the new emptDir mounts

Benefits

• people using a policy to enforce sizelimit don't run in policyviolations anymore
• k8s nodes filesystem protected from filling up by accident

Possible drawbacks

Applicable issues

• fixes: https://github.com/bitnami/charts/issues/28742

Additional information

Checklist

• [x] 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
• [x] Title of the pull request follows this pattern [bitnami/<name_of_the_chart>] Descriptive title
• [x] All commits signed off and in agreement of Developer Certificate of Origin (DCO)