fff-web: Show WiFi channels and SSID

This patch introduced more detailed information about the
hood in the WebUI, i.e. channel and SSIDs.

The patch includes a reorganization of the columns.

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
Tested-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
Reviewed-by: Tim Niemeyer <tim@tn-x.org>
Tested-By: Fabian Bläse <fabian@blaese.de>