Improve Merge entries

[l2eused]

Describe your suggested feature

tbc, merge entry mean the entry that's have merged entries inside.

Improve merge feature

• In merge entry, allow to filter merged (only show some merged entries like scanlator filter). p.s related to #84 but I supposed that suggestion mean in library page not entry page.
• In browse page, show merged entry as added to library entry style. e.g low opacity, have merge icon on the top left. This will prevent user to add already merged entry to their library without notice and duplicate them. (would be great if it can show caution screen when duplicate add, like already in library alert.)

Other details

Currently, the entry that's merged will not shown as already have in library in browse page. Moreover, app wasn't notice and give popup duplicate in library at all.

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 1.11.2.
• [X] I will fill out all of the requested information in this form.