feat(ImageProvider): add bitmapLrucache size setting

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

@@ -991,5 +991,7 @@
     <string name="download_book_fail">Download Fail</string>
     <string name="upload_to_remote">Upload</string>
     <string name="add_remote_book">WebDavBook</string>
+    <string name="bitmap_cache_size_summary">Current cache max size %1$s MB</string>
+    <string name="bitmap_cache_size">bitmap cache size</string>
     <!-- string end -->
 </resources>