purged orphaned message copies that were introduced by UI refactorings

A lot of messages remained in their old locations when UI refactorings occurred. In some cases this happened successively, leaving more than one occurrence of orphans behind.

I tracked some candidates, mostly from the global configuration page and GlobalSecurityConfiguration.
In cases where I could find the new location I removed the orphans.
In some cases I could add translations to the new locations using existing translations.

The purged messages are now located in GlobalSCMRetryCountConfiguration, GlobalQuietPeriodConfiguration, GlobalCloudConfiguration, GlobalNodePropertiesConfiguration, MasterComputer, GlobalCrumbIssuerConfiguration, GlobalDefaultViewConfiguration, ViewsTabBar, MyViewsTabBar, UsageStatistics, ToolInstallation