Add possibly to mount custom secrets

[janwels89]

This change allows to mount custom secrets in to the anything-llm container

I needed this to apply a custom root ca via NODE_EXTRA_CA_CERTS

example values file:

persistence:
  enabled: true
  accessMode: ReadWriteOnce
  size: 10Gi
  volumes:
    - name: server-storage
      mountPath: /app/server/storage
      claimName: server-storage
    - name: ca-cert
      secretName: ca-bundle
      mountPath: /etc/ssl/certs/ca-certificates.crt
      subPath: ca-certificates.crt

config:
  NODE_EXTRA_CA_CERTS: /etc/ssl/certs/ca-certificates.crt
  

i don't know if this solution is correct, input appreciated. works for me on my cluster.