Add support for the epub format.

Describe your suggested feature

I understand Tachiyomi is first and foremost a manga reader. I would however appreciate it immensely if you could add basic epub support. Tachiyomi plugins like Kavita make it possible to access and import Light novels and other books to Tachiyomi. However reading them is currently impossible (you can open them but the reader will only recognize the images).

There are next to no open source ereaders with opds support on Android. Adding support for the epub format - which is standardized and open and in essence a zip file - to Tachiyomi would significantly improve the application for me and other novel readers.

This could also pave the way for future plugins specifically for browsing Light Novels as well as books from projects like Gutenberg. That is however not within the scope of this request but a mere thought.

Love the fork. Thanks for developing it.

Other details

No response

Acknowledgements

[X] I have searched the existing issues and this is a new ticket, NOT a duplicate or related to another open or closed issue.
[X] I have written a short but informative title.
[X] If this is an issue with an extension, I should be opening an issue in the extensions repository.
[X] I have updated the app to version 1.9.3.
[X] I will fill out all of the requested information in this form.

jobobby04 / TachiyomiSY