Currently when the app starts, the scaling of all monitors gets changed
to a combobox value. This change makes it so that only the primary
monitor is affected, and that it only sets the scaling when the user
interacts with the combobox.
This is partially an emergency fix also for
https://invent.kde.org/plasma/plasma-mobile/-/issues/404, which was
potentially introduced by https://invent.kde.org/plasma/plasma-mobile/-/merge_requests/582
This MR extracts the screen brightness implementation from initialstart
to a QML plugin, and also ports the action drawer brightness slider
implementation to it. This avoids importing the powerdevil screen
brightness plugin on the lockscreen, which apparently has a race
condition that causes it to sometimes segfault.
Adds an experience for users on first login, allowing some basic configuration.
This is separate from a first start wizard, which would run as a separate user with elevated permissions, and include options that an installer would have.
