Interface Kit: add default dark appearence color constants

Change-Id: I8added6ada702eb09e95f5f2d6e34b748067c6bc
Reviewed-on: https://review.haiku-os.org/c/haiku/+/4571
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>
Reviewed-by: Adrien Destugues <pulkomandy@pulkomandy.tk>

* There is now a server_read_only_memory structure that is placed in a (surprise!)
read-only area shared between the Desktop and all applications.
* Right now, this area only contains the desktop colors, ie. B_PANEL_BACKGROUND_COLOR
etc.; ui_color() no longer needs to ask the server for these colors.
* The ui_colors are now maintained by DesktopSettings, though ColorSet is still there.
* The default colors are now hardcoded once and for everyone in InterfaceDefs.h, ie.
the app_server uses them as well.
* Desktop::Init() can now also return an error (but that is not yet accounted for).
* Cleaned up InterfaceDefs.h.
* Fixed wrong include in moreUTF8.h.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@17232 a95241bf-73f2-0310-859d-f6bbb57e9c96

* There is now a server_read_only_memory structure that is placed in a (surprise!)
read-only area shared between the Desktop and all applications.
* Right now, this area only contains the desktop colors, ie. B_PANEL_BACKGROUND_COLOR
etc.; ui_color() no longer needs to ask the server for these colors.
* The ui_colors are now maintained by DesktopSettings, though ColorSet is still there.
* The default colors are now hardcoded once and for everyone in InterfaceDefs.h, ie.
the app_server uses them as well.
* Desktop::Init() can now also return an error (but that is not yet accounted for).
* Cleaned up InterfaceDefs.h.
* Fixed wrong include in moreUTF8.h.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@17232 a95241bf-73f2-0310-859d-f6bbb57e9c96