Unified log file for software management operations

[albinsuresh]

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

When a software management operation like software update is executed, two different log files are generated at /var/log/tedge/agent directory:

1. The plugin execution log: software-update-YY-MM-DD:HH:MM:SS.log
2. The workflow log: workflow-software_update-c8y-mapper-YY-MM-DD:HH:MM:SS.log

This makes debugging harder as the user needs to gather both the logs and correlate them.

Describe the solution you'd like

Integrate the plugin execution log also into the workflow log itself.