Merge pull request #7220 from thundernest/extract_settings_upgrader

.../com/fsck/k9/preferences/AccountSettingsDescriptions.java

.../com/fsck/k9/preferences/GeneralSettingsDescriptions.java

app/core/src/main/java/com/fsck/k9/preferences/Settings.java

.../k9/preferences/upgrader/AccountSettingsUpgraderTo53.java

.../k9/preferences/upgrader/AccountSettingsUpgraderTo54.java

.../k9/preferences/upgrader/AccountSettingsUpgraderTo74.java

.../k9/preferences/upgrader/AccountSettingsUpgraderTo80.java

.../k9/preferences/upgrader/AccountSettingsUpgraderTo81.java

.../k9/preferences/upgrader/GeneralSettingsUpgraderTo24.java

.../k9/preferences/upgrader/GeneralSettingsUpgraderTo31.java

.../k9/preferences/upgrader/GeneralSettingsUpgraderTo58.java

.../k9/preferences/upgrader/GeneralSettingsUpgraderTo69.java

.../k9/preferences/upgrader/GeneralSettingsUpgraderTo79.java

...om/fsck/k9/preferences/migrations/StorageMigrationTo11.kt