proofread/update kalarm docbook for kf5

remove entities kappname + package, not used in kf5
bump date + releaseinfo
remove obsolete options
add missing option --triggerEvent
replace Help options with qt5options + kf5options
remove KResources related stuff
remove &reporting.bugs; + &updating.documentation;, not used in kf5
fix path for kalarm files
remove appendix installation, outdated
update screenshots
REVIEW:129621