Kiwix Android App UX Improvement

Create a new initial landing page with suggested ZIM files that a user might want to download and improve the download management UI to flow more intuitively, guiding users to get the content that they want.
Make the switching of tabs more intuitively and also show the preview of tabs.
Improve language selection functionality allowing users to find the supported languages easily.
Improve the bottom toolbar to make it more user-friendly.
Improve the bookmarks screen with an option to show bookmarks from the current ZIM file or from all ZIM files.
Add a screen to show the history of pages visited by the user.
Move help to a separate screen.