* Refactored the test cases for this new change.
* Now user can easily import the exported bookmarks by just selecting the exported `bookmark.xml` file.
* The application now exports 'bookmark.xml' file to the 'Android/media/org.kiwix...' folder. Users can copy this file to the 'Android/data/org.kiwix.../files/Bookmarks/' folder to view the exported bookmarks.
* Introduced an export bookmark feature in the settings screen, allowing users to easily export all bookmarks with a simple click. A dialog prompt appears before exporting, indicating the location where the exported bookmarks will be saved and providing instructions on how to import them.
* Added a test case for this change in our settings test.
* We have refactored our code to use PageDao for managing data related to Bookmarks, Notes, and History. With the ability to return Flowable from the Room database, the BasePageDao interface has become unnecessary. Consequently, we have removed BasePageDao and streamlined our code to use PageDao, providing a unified approach for these functionalities. This change reduces code complexity and enhances readability, making the codebase easier to understand and maintain.
* We have moved the deleting functionality to background thread because we should not perform any database operation on UI thread.
* Refactored all the test cases according to this change.
* Improved the migration code of recent searches, now all the migration will be performed on the background thread so that it can not impact the UI thread.
* Removed unnecessary logs.
* Introduced the `ObjectBoxToRoomMigrator` class for migrating the recent search data from objectBox to room.
* Fixed the deprecation code error was showing due to `RecentSearchEntity`.
* Fixed the fullScreen mode not properly working on Android 11 and above(It was showing the blue line on the top), and also not showing the navigation options so that the user can close the `fullScreenMode` while pressing the back button in the navigation. Now it started showing the `fullScreenMode` like in earlier version of kiwix.
* Also improved the `fullScreenMode` for lower versions of Android. We have created an extension function so that we can easily reuse the code when we open/close the `fullScreenMode` for a video.
* Fixed the BottomToolbar's options was showing when the application is in the background in `fullScreenMode` and the user opens again the application.
* When the application is running in the `fullScreenmode` and we close the `fullScreenMode` of a video so at that time BottomToolbar's option was showing. So we have fixed that.
