matplotlib failed to create dir using helm charts

[louisgls]

Describe the bug

I'm using the helm chart version 0.3.3 and i have the following errors on backend container :

mkdir -p failed for path /.config/matplotlib: [Errno 30] Read-only file system: '/.config'                                                                                                                                                  
Matplotlib created a temporary cache directory at /tmp/matplotlib-mlxbt7nk because there was an issue with the default path (/.config/matplotlib); it is highly recommended to set the MPLCONFIGDIR environment variable to a writable direc
tory, in particular to speed up the import of Matplotlib and to better support multiprocessing.                                                                                                                                             
Fontconfig error: No writable cache directories     

Applications works but it is slow without cache. I've set it up using databaseType: pgsql and disabled sqlite and localStorage:

    persistence:
      sqlite:
        enabled: false
      localStorage:
        enabled: false

I'm also running it in a restricted environnement so I have to apply securityContext ( I used the one commented in the chart) :

    containerSecurityContext:
      seLinuxOptions: {}
      runAsUser: 1001
      runAsGroup: 1001
      runAsNonRoot: true
      privileged: false
      readOnlyRootFilesystem: true
      allowPrivilegeEscalation: false
      capabilities:
        drop: ["ALL"]
      seccompProfile:
        type: "RuntimeDefault"

This is probably the reason why the folder can't be created.
Am I doing it right ?

To Reproduce
Helm chart 0.3.3 with security context and pgsql backend.

Expected behavior
I'm expecting the cache to work.

[Nathanael-Mtd]

Right now, containerSecurityContext settings are not usable, we should wait completion of PR #1589
Also, some changes need to be done on code to move that .config folder to /tmp folder