Remove dependencies on luci.util (and partly nixio.fs) from announce scripts

package/gluon-announce/files/lib/gluon/announce/collect.lua

...nounce/files/lib/gluon/announce/nodeinfo.d/hardware/nproc

...nce/files/lib/gluon/announce/nodeinfo.d/software/firmware

...unce/files/lib/gluon/announce/nodeinfo.d/system/site_code

...n-announce/files/lib/gluon/announce/statistics.d/idletime

...on-announce/files/lib/gluon/announce/statistics.d/loadavg

...uon-announce/files/lib/gluon/announce/statistics.d/memory

...-announce/files/lib/gluon/announce/statistics.d/processes

...uon-announce/files/lib/gluon/announce/statistics.d/uptime

package/gluon-announce/files/usr/lib/lua/gluon/announce.lua

package/gluon-core/files/usr/lib/lua/gluon/util.lua

...man-adv-core/files/lib/gluon/announce/neighbours.d/batadv

...atman-adv-core/files/lib/gluon/announce/neighbours.d/wifi

...ib/gluon/announce/nodeinfo.d/network/mesh/bat0/interfaces

...les/lib/gluon/announce/nodeinfo.d/network/mesh_interfaces

...lib/gluon/announce/nodeinfo.d/software/batman-adv/version

...an-adv-core/files/lib/gluon/announce/statistics.d/gateway

...-fastd/files/lib/gluon/announce/nodeinfo.d/software/fastd

...-vpn-fastd/files/lib/gluon/announce/statistics.d/mesh_vpn