[Debugger] Move servers-related behaviours to ServersDebugger.

Forcing draw during debug break is now handled by ServersDebugger, and
only happens when the proper message is sent from the EditorDebugger
("servers:draw").
In a similar way, briging the window in foreground is now also handled
by ServersDebugger upon receiving "servers:foreground" which is sent by
the EditorDebugger when resuming from a break ("continue").

servers/debugger/servers_debugger.h

@@ -33,6 +33,8 @@
 
 #include "core/debugger/debugger_marshalls.h"
 
+#include "servers/rendering_server.h"
+
 class ServersDebugger {
 public:
 	// Memory usage
@@ -108,6 +110,7 @@ private:
 	class ServersProfiler;
 	class VisualProfiler;
 
+	double last_draw_time = 0.0;
 	Ref<ServersProfiler> servers_profiler;
 	Ref<VisualProfiler> visual_profiler;