Support uploading workflow logs from child devices

[reubenmiller]

Is your feature request related to a problem? Please describe.

thin-edge.io supports automatically uploading the associated workflow log file on failure via the following setting:

c8y.operations.auto_log_upload=on-failure

Currently this feature has the limitation that it only works on the main device, as the tedge-mapper-c8y reads the command's .logPath property, and checks if the paths exists (on the main device), then uploads it. When an operation is sent to a child device which is running the tedge-agent, the log file referenced in the operation only exists on the child device, and is not accessible to the tedge-mapper-c8y. Below is an example of an operation sent to the child device with the reference to the .logPath which the mapper does not have access to:

[te/device/child02///cmd/shell_execute/c8y-mapper-42785332] {"@version":"f787c5d1a37d27d6d19fd6b9dffea6449e2ec46e6caa35cf1fdb76c7be2773f0","c8y-mapper":{"on_fragment":"c8y_Command","output":"${.payload.result}"},"command":"exit 1","logPath":"/var/log/tedge/agent/workflow-shell_execute-c8y-mapper-42785332.log","reason":"shell_execute.sh returned exit code 1","status":"failed"}

Describe the solution you'd like

thin-edge.io should support a way for child devices to send their log files so that the tedge-mapper-c8y can upload them to Cumulocity. A logical fit would be using the File Transfer Service for this, but for that to work, the tedge-mapper-c8y should inject a property which includes the URL where log files can be uploaded to from the child device.

Describe alternatives you've considered

Additional context