Add Dual-Page Reading Mode for mihon

[8620hachiroku]

Describe your suggested feature

Dear mihon developers,

I propose adding dual-page reading mode for landscape orientation to maximize screen usage and enhance the reading experience. This feature would cater to users who frequently read lengthy documents or engage in research.

Other details

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Acknowledgements

• I have searched the existing issues and this is a new ticket, NOT a duplicate or related to another open or closed issue.
• I have written a short but informative title.
• I have updated the app to version 0.16.5.
• I will fill out all of the requested information in this form.

[Norsze]

Duplicate of #589