Addition of Confirm Exit toggle

[SaisuryaL]

Describe your suggested feature

Tachiyomi had a confirm exit toggle which is currently missing in Mihon. It would be good to have the option to prevent accidentally exiting the app while swiping back.

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 official extension, I should be opening an issue in the extensions repository.
• [X] I have updated the app to version 0.16.0.
• [X] I will fill out all of the requested information in this form.

[MajorTanya]

(my comment copied from #173 where I commented before seeing this issue)

This feature was removed in https://github.com/mihonapp/mihon/commit/8f4bc71cf7b99fe0b0d2ea68dfca0140477686cc because it was deemed redundant with Android's Predictive Back feature when using gesture navigation, just to assure you it used to exist. 👍

I don't know if there would be a way to bring this feature back that doesn't clash with this predictive back feature, though, so I can't give you a definitive yes/no on whether it can be brought back.