gluon-alfred: reduce usage of util.exec, improve table formatting

...lfred/files/lib/gluon/alfred/announce.d/software/firmware

...red/files/lib/gluon/alfred/announce.d/statistics/idletime

...fred/files/lib/gluon/alfred/announce.d/statistics/loadavg

...lfred/files/lib/gluon/alfred/announce.d/statistics/uptime

...er/files/lib/gluon/alfred/announce.d/software/autoupdater

...adv/files/lib/gluon/alfred/announce.d/software/batman-adv

...-adv/files/lib/gluon/alfred/announce.d/statistics/traffic

...pn-fastd/files/lib/gluon/alfred/announce.d/software/fastd

...luon-node-info/files/lib/gluon/alfred/announce.d/location