### What problem does this PR solve?
Switch to Kubernetes StatefulSet resources for MySQL, Minio and vector
DB since these are stateful application components. This makes
operations such as helm upgrade smoother since the default container
update strategy becomes a sequential rolling update of each pod.
Also fixes a bug in the name template for the Minio stateful set
resource to align it with the naming convention used for other
components.
### Type of change
- [X] Bug Fix (non-breaking change which fixes an issue)
Modified the chart to retain persistent volumes by default when the
chart is uninstalled, following established best practices in the Helm
community (e.g., Bitnami charts)
### What problem does this PR solve?
Previously, deleting the helm chart would automatically remove all
persistent data, which poses a risk of accidental data loss.
### Rationale
This change aligns with industry standards to safeguard data by
requiring explicit action to remove persistence, rather than making
deletion the default behavior.
### Impact:
Users who intentionally want to remove persistent data will need to do
so manually or by setting appropriate flags during chart uninstallation.
### Type of change
- [ ] Bug Fix (non-breaking change which fixes an issue)
- [x] New Feature (non-breaking change which adds functionality)
- [ ] Documentation Update
- [ ] Refactoring
- [ ] Performance Improvement
- [ ] Other (please describe):
### What problem does this PR solve?
Add's a Helm chart for deploying RAGFlow on Kubernetes.
Closes#864.
### Type of change
- [X] New Feature (non-breaking change which adds functionality)
