fix: 增加设置是否显示最近打开区域的接口

1.增加本地配置，并增加bool类型变量来表示是否显示最近打开应用
2.在应用打开或者退出的时候，根据是否显示最近打开应用的配置来决定是否显示当前应用图标

Log: 增加是否显示最近打开应用接口
Influence: 时尚模式下，调用setShowRecent接口，观察任务栏是否显示最近打开应用
Bug: https://pms.uniontech.com/bug-view-147717.html
Change-Id: I9e2f8a8ea74bf4deb2f1db9af8b87ff1827c2297

misc/dconf/com.deepin.dde.dock.json

@@ -151,6 +151,16 @@
 			"description": "The apps which has been opened recently when dock is started",
 			"permissions": "readwrite",
 			"visibility": "private"
+		},
+		"Show_Recent": {
+			"value": false,
+			"serial": 0,
+			"flags": [],
+			"name": "Show_Recent",
+			"name[zh_CN]": "*****",
+			"description": "show or hide recent app in dock",
+			"permissions": "readwrite",
+			"visibility": "private"
 		}
 	}
 }