app_server: don't reset brightness when switching workspaces

Fixes #16538.

app_server: save/restore screen brightness settings

The brightness is saved in the screen configurations of the first
workspace. For now, all screens get the same brightness (I can't get
screen IDs to work today). Since we only support setting the brightness
for laptop displays for now, this shouldn't matter. It can be fixed when
app_server gets actual multiple display support.

Fixes #14254

Change-Id: Ib33aa65a73407a65bd469d0efa8542210fec02d4
Reviewed-on: https://review.haiku-os.org/c/haiku/+/362
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>

* ServerApp now maintains a mask of workspaces with temporary mode settings,
and reverts the modes if the app goes away (ie. if it crashes).
* Desktop::SetScreenMode() also set the mode on the current screen, even if
it should have been set on another screen.
* Cleaned up the Desktop.h header.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@32564 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Rewrote screen configuration management: VirtualScreen doesn't have anything
to do with the configurations now, instead, there is a separated
ScreenConfigurations class that maintains all known screen_configurations
per workspace (and the Workspace::Private class has two of them, one for the
current modes, one for the stored modes).
* Added Desktop::{Get|Set}ScreenMode() methods, ServerApp now only calls those.
* Getting and setting of anything else than the current screen is now supported.
* This change also fixes that a temporarily set screen mode was not being
restored on workspace switch.
* Also, the Deskbar now seems to have the wrong location a lot, which is
something that should be easily fixable therefore. I will look into this next.
* Got rid of the unhandy screen_id structure server side, and in BPrivateScreen;
we now just use an int32 - the next API break should definitely replace the
screen_id with a simple typedef.
* Some cleanup.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@32541 a95241bf-73f2-0310-859d-f6bbb57e9c96

* ServerApp now maintains a mask of workspaces with temporary mode settings,
and reverts the modes if the app goes away (ie. if it crashes).
* Desktop::SetScreenMode() also set the mode on the current screen, even if
it should have been set on another screen.
* Cleaned up the Desktop.h header.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@32564 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Rewrote screen configuration management: VirtualScreen doesn't have anything
to do with the configurations now, instead, there is a separated
ScreenConfigurations class that maintains all known screen_configurations
per workspace (and the Workspace::Private class has two of them, one for the
current modes, one for the stored modes).
* Added Desktop::{Get|Set}ScreenMode() methods, ServerApp now only calls those.
* Getting and setting of anything else than the current screen is now supported.
* This change also fixes that a temporarily set screen mode was not being
restored on workspace switch.
* Also, the Deskbar now seems to have the wrong location a lot, which is
something that should be easily fixable therefore. I will look into this next.
* Got rid of the unhandy screen_id structure server side, and in BPrivateScreen;
we now just use an int32 - the next API break should definitely replace the
screen_id with a simple typedef.
* Some cleanup.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@32541 a95241bf-73f2-0310-859d-f6bbb57e9c96