Update kinfocenter docbook to 5.12
proofread
bump date + realeaseinfo
kde -> plasma
add energy + fileindexer+wayland
group subitems to Device / Network / Graphical items
Differential Revision: https://phabricator.kde.org/D11864
(cherry picked from commit 5d247348141276d76f465ca82294ccec5b812e67)
backport to stable 5.12 lts