libobs-d3d11: Set maximum GPU priority

(This commit also modifies the UI)

This solves the issue where OBS would be deprioritized by Windows over
fullscreen games, causing OBS to lag out whereas the games would still
run fine.

UI/obs-app.cpp

@@ -1911,6 +1911,18 @@ static void load_debug_privilege(void)
 				      NULL);
 	}
 
+	if (!!LookupPrivilegeValue(NULL, SE_INC_BASE_PRIORITY_NAME, &val)) {
+		tp.PrivilegeCount = 1;
+		tp.Privileges[0].Luid = val;
+		tp.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED;
+
+		if (!AdjustTokenPrivileges(token, false, &tp, sizeof(tp), NULL,
+					   NULL)) {
+			blog(LOG_INFO, "Could not set privilege to "
+				       "increase GPU priority");
+		}
+	}
+
 	CloseHandle(token);
 }
 #endif