Add navigation to Last/First page #1629

Do you follow the guidelines?

[x] I have tested my changes
[x] There is no breaking changes (to the best of my knowledge)
[x] I really tested my changes and there is no regression (tested running on my local deployment 55k history items, ~2k unread items)
[ ] Ideally, my commit messages use the same convention as the Go project: https://go.dev/doc/contribute#commit_messages
[x] I read this document: https://miniflux.app/faq.html#pull-request (I hope it's not "Radical user interface changes" nor would it slow down the miniflux)

I tried to solve #1629 and #1867

I made a couple of changes:

added parent <div/>s for pagination sections to make aligning it easier/more sensible when grouped
changed symbols from » to › (for forward/next navigation) and from « to ‹ (for backward/previous navigation) as IMHO it's more sensible (single character indicates shorter jump while double character indicates bigger jump; AFAIK it's quite common practice when doing navigation)
I wasn't sure how to handle i18n and I added the items to all lang files

One thing that works "iffy" right now is marking last page as read - when that happens when last page is marked as read - currently it goes to first page. I was thinking that if offset > total/unread it should go to the last available page, but even though this results in "There are no unread entries." (currently) as it has offset same as total/unread. One solution would be to add pagination to internal/template/templates/views/unread_entries.html and internal/template/templates/views/feed_entries.html which makes it possible to go to previous page easily (I have it locally and it it "is working" but it feels kinda hacky…)

miniflux / v2

Add navigation to Last/First page #1629 #2707