✨ Feature(custom): add image watermark opacity setting

ISSUES CLOSED: #348

src/renderer/i18n/locales/en.json

@@ -104,7 +104,8 @@
           "bottomLeft": "Bottom Left",
           "bottomRight": "Bottom Right",
           "center": "Center"
-        }
+        },
+        "imageOpacity": "Watermark Opacity"
       },
       "transform": {
         "title": "Transform Settings",

src/renderer/i18n/locales/zh-CN.json

@@ -104,7 +104,8 @@
           "bottomLeft": "左下",
           "bottomRight": "右下",
           "center": "中"
-        }
+        },
+        "imageOpacity": "水印透明度"
       },
       "transform": {
         "title": "变换设置",

src/renderer/i18n/locales/zh-TW.json

@@ -104,7 +104,8 @@
           "bottomLeft": "左下",
           "bottomRight": "右下",
           "center": "中"
-        }
+        },
+        "imageOpacity": "水印透明度"
       },
       "transform": {
         "title": "變換設置",