coreApp->setOrganizationDomain() expects the domain
in DNS order (hohnstaedt.de) and not reversed.
Change the WM_CLASS property to "de.hohnstaedt.xca"
via setApplicationName().
While Qt6 prepends the reversed "OrganizationDomain",
Qt5 does not and setting the complete name with
domain-prefix works for both.
Also adopt the ".desktop" file name to follow the application-name
and fix issues found by "desktop-file-validate"
Put it into the "PlugIns" directory and load it from there.
Show whether the legacy-provider was loaded in the About-Dialog.
CmakeLists.txt: Improve OpenSSL Major version detection
and replace the foreach() loop in misc/CMakeLists.txt
by the simpler list(TRANSFORM ...)
The long list of translations and html documentation
pages is now auto-generated by the cmake files,
which know the translations and html files. (DRY)
TODO: Windows SQL drivers for mysql and psql