Set CWD to storage dir

[hardillb]

part of FlowFuse/flowfuse#3056

Description

Ensure that the Node-RED CWD is userDir/storage so files written without a path end up on the persistent volume.

DO NOT MERGE BEFORE ALL THE DRIVERS ARE UPDATED I will add a check list for this.

Related Issue(s)

Checklist

• [x] I have read the contribution guidelines
• [ ] Suitable unit/system level tests have been added and they pass
• [ ] Documentation has been updated
  • [ ] Upgrade instructions
  • [ ] Configuration details
  • [ ] Concepts
• [ ] Changes flowforge.yml?
  • [ ] Issue/PR raised on FlowFuse/helm to update ConfigMap Template
  • [ ] Issue/PR raised on FlowFuse/CloudProject to update values for Staging/Production

Labels

• [ ] Includes a DB migration? -> add the area:migration label

Merge first

• [x] https://github.com/FlowFuse/driver-localfs/pull/135
• [x] https://github.com/FlowFuse/helm/pull/407
• [x] https://github.com/FlowFuse/driver-k8s/pull/163

[knolleary]

@hardillb Approved - will let you merge given the warnings above