Volume Mounts for Local Runs

[lkingland]

Currently, runtime volumes defined in func.yaml are ignored when running functions locally with func run.

We should update pkg/docker/runner.go -> newHostConfig() to configure volumes in addition to the ports it currently defines.

1. ConfigMap → Local .func/run/configmaps/<name> directory
2. Secret → Local .func/run/secrets/<name> directory
3. EmptyDir → Docker tmpfs or anonymous volume
4. PersistentVolumeClaim → Named Docker volume or local directory

Additionally, we could consider adding a new volume type specifically for local development:

volumes:
  - hostPath: /local/path
    path: /container/path

Implementation Notes:

There should be warnings when defined resources are note available locally, but not fail.

Should disallow mapping of directories outside of .func for security (example risk: user downloads a malicious function, runs it locally, accessing sensitive areas of the FS and exfiltrating via the funciton source implementation)

Current Workarounds

1. Use the "host" builder (loses container isolation)
2. Run func build then manually docker run -v local:container image
3. Deploy to a test cluster for volume testing