Optimizations / XFS filesystem is strongly recommended

## Steps to reproduce
Just deploy mongodb and connect to it

## Expected behavior
I think we should autoconfigure or document recommended filesystem

## Actual behavior
I get the following warning when connecting to Mongodb
```
2024-11-28T21:05:14.553+00:00: Using the XFS filesystem is strongly recommended with the WiredTiger storage engine. See http://dochub.mongodb.org/core/prodnotes-filesystem
```

## Versions
Juju 3.5.4
```
data-integrator active 1 data-integrator latest/stable 41 no
grafana-agent active 3 grafana-agent latest/edge 299 no tracing: off
mongodb active 3 mongodb 6/stable 199 no
self-signed-certificates active 1 self-signed-certificates latest/stable 155 no
```

The issue names MongoDB 6, the WiredTiger storage engine, and the XFS filesystem warning; start by reviewing how this charm configures MongoDB deployment and where its operator documentation is maintained. Clarify whether the accepted scope is automatic filesystem configuration or documentation, then verify that the warning is addressed or the recommendation is documented.

Written by the indexing model from the issue text.