Fix error messages not being displayed in the preferences configuration
git: Ignore git related files on export
Fix word wrapping in perfdata labels and values

fixes #6377
Fix monitoring backend configuration not showing resource selection fields

fixes #6448
Make Icinga\Logger\Writer\FileWriter output more useful error messages

fixes #6464
Ensure that our menu inis are in sync and up2date

The menu configurations for vagrant missed the entries for the timeline,
applicationlog and contacts-view.

fixes #6512
Perfdata plugin should also have a knowledge about labels

Prior to this change the PerfdataSet only knew the labels of a performance
data value which prevented the Perfdata object from being used
individually.

refs #6515
Do not show pie charts for perfdata values when no percentage is available

refs #6515
Improve piechart limitation and show non-piechart perfdata as well

The perfdata helper did an improper limitation as it might have skipped
valid values due to applying the limit before the filter. When not in compact
view the helper now also shows non-piechart values by using their raw
representation.

refs #6515
Merge branch 'bugfix/show-non-piechart-perfdata-not-as-piechart-6515'

fixes #6515
Display statehistory summary vertically

fixes #6636
Make contacts' view work like the downtimes' one

fixes #6513
Provide a template for our license headers

refs #6309
Allow empty license headers being applied to files

refs #6309
Drop public/css/icinga/actiontable.less as its not in use anywhere
Remove license headers from all files

refs #6309
Merge branch 'bugfix/light-file-header-6309'

fixes #6309
Improve preference changeset calculation

The calculation is still subject to the concrete writer implementation as its
parent Icinga\User\Preferences\PreferencesStore is only an abstraction
layer without any knowledge how the data is actually stored so it is not able
to determine how to handle differences.

fixes #6220
Make contacts' view look more like contactgroups' view
Small fixes