### Describe Your Changes
This PR adds the feature to parse a multi yaml doc following the
`\n---\n`
The issue is
[6753](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/6753)
### Checklist
The following checks are **mandatory**:
- [x] My change adheres [VictoriaMetrics contributing
guidelines](https://docs.victoriametrics.com/contributing/).
---------
Signed-off-by: kirti purohit <kirti.purohit@hpe.com>
Co-authored-by: kirti purohit <kirti.purohit@hpe.com>
Co-authored-by: Jiekun <jiekun@victoriametrics.com>
Co-authored-by: hagen1778 <roman@victoriametrics.com>
(cherry picked from commit 008b649658)
