cockpit plugin: Flight stack logs

[anselmolsm]

Allow access to system and flight stack logs.

@lucasdemarchi @lfelipe , pls add more details.

[lfelipe]

Idea is to initially just provide easy access to the log files that were recorded on the platform so the user can download them without too much of a hassle. Later on to actually provide better log information through the interface.

[lucasdemarchi]

Renamed the issue to be clear this is about flight stack logs. We already have a plugin enabled to check the system logs.

[anselmolsm]

A first PR related to this task: intel-aero/aero-cockpit-plugins#6