feat(book/cache): add export picture option

app/src/main/res/menu/book_cache.xml

@@ -36,12 +36,19 @@
         android:title="@string/export_to_web_dav"
         android:checkable="true"
         app:showAsAction="never" />
+
     <item
         android:id="@+id/menu_export_no_chapter_name"
         android:title="@string/export_no_chapter_name"
         android:checkable="true"
         app:showAsAction="never" />
 
+    <item
+        android:id="@+id/menu_export_pics_file"
+        android:title="@string/export_pics_file"
+        android:checkable="true"
+        app:showAsAction="never" />
+
     <item
         android:id="@+id/menu_export_folder"
         android:title="@string/export_folder"

app/src/main/res/values-es-rES/strings.xml

@@ -991,6 +991,7 @@
     <string name="bitmap_cache_size_summary">Current cache max size %1$s MB</string>
     <string name="bitmap_cache_size">bitmap cache size</string>
     <string name="restart_to_apply_changes">Restart to apply changes</string>
+    <string name="export_pics_file">Export Picture Files</string>
     <!-- string end -->
 
 </resources>

app/src/main/res/values-ja-rJP/strings.xml

@@ -994,6 +994,8 @@
     <string name="bitmap_cache_size_summary">Current cache max size %1$s MB</string>
     <string name="bitmap_cache_size">bitmap cache size</string>
     <string name="restart_to_apply_changes">Restart to apply changes</string>
+    <string name="export_pics_file">Export Picture Files</string>
     <!-- string end -->
 
+
 </resources>

app/src/main/res/values-pt-rBR/strings.xml

@@ -994,6 +994,7 @@
     <string name="bitmap_cache_size_summary">Current cache max size %1$s MB</string>
     <string name="bitmap_cache_size">bitmap cache size</string>
     <string name="restart_to_apply_changes">Restart to apply changes</string>
-
+    <string name="export_pics_file">Export Picture Files</string>
     <!-- string end -->
+
 </resources>

app/src/main/res/values-zh-rHK/strings.xml

@@ -991,6 +991,7 @@
     <string name="bitmap_cache_size_summary">当前最大缓存 %1$s MB</string>
     <string name="bitmap_cache_size">图片绘制缓存</string>
     <string name="restart_to_apply_changes">重启应用更改</string>
-
+    <string name="export_pics_file">TXT导出图片</string>
     <!-- string end -->
+
 </resources>

app/src/main/res/values-zh-rTW/strings.xml

@@ -993,6 +993,7 @@
     <string name="bitmap_cache_size_summary">当前最大缓存 %1$s MB</string>
     <string name="bitmap_cache_size">图片绘制缓存</string>
     <string name="restart_to_apply_changes">重启应用更改</string>
-
+    <string name="export_pics_file">TXT导出图片</string>
     <!-- string end -->
+
 </resources>

app/src/main/res/values-zh/strings.xml

@@ -993,6 +993,7 @@
     <string name="bitmap_cache_size_summary">当前最大缓存 %1$s MB</string>
     <string name="bitmap_cache_size">图片绘制缓存</string>
     <string name="restart_to_apply_changes">重启应用更改</string>
-
+    <string name="export_pics_file">TXT导出图片</string>
     <!-- string end -->
+
 </resources>

app/src/main/res/values/strings.xml

@@ -994,6 +994,8 @@
     <string name="bitmap_cache_size_summary">Current cache max size %1$s MB</string>
     <string name="bitmap_cache_size">bitmap cache size</string>
     <string name="restart_to_apply_changes">Restart to apply changes</string>
+    <string name="export_pics_file">Export Picture Files</string>
     <!-- string end -->
 
+
 </resources>