Add some local commands to be used by local administrators

[rene]

Eventually, an edge device can be touched by a local administrator (maybe for debugging purposes, for instance). Implement some local admin commands would help these admins and/or developers to debug issues or to perform a recovery, etc. These local admin commands would allow:

• Fetch and show logs locally in a more human readable format
• Trigger some specific EVE actions, such as force fetching configuration from controller, upload logs, fetch Edge App images, etc…
• Force to fetch and show status of Edge Applications (like is shown periodically)
• Easily fetch specific configuration files for debug, like the xen?.cfg, network config files, without the needs to know the specific path of each one of them

[milan-zededa]

For the networking part of EVE, here are some proposed commands that would be very helpful: https://wiki.lfedge.org/pages/viewpage.action?pageId=99877847