Add option to mark all items read

[Shiandow]

Since it was inconvenient to have to open each page in order to mark them read I've added a context menu item to mark items as read.

Unfortunately I wasn't able to add all of the corresponding locales entries for it as I do not speak most of those languages. It works fine in English.

[Shiandow]

This solves #213.

[nt1m]

Looks good, thanks. Just one small comment.

Happy holidays btw! Sorry it took me a while to get to this.

[Shiandow]

Hey, no problems, given the holidays I wasn't expecting a quick reply.

I've added your suggested change.

Happy holidays to you too!

[nt1m]

@evilpie wdyt of this PR? It does what it should, but not sure it's going to be expected for users to have their history filled when they click this item

[evilpie]

I have the same concern. Maybe we could make this side-effect more obvious with some different language like "Mark all as read/visited", but I honestly don't like that phrasing myself.

Maybe it's fine to add, worst case you can always delete something from your history?

[sukiletxe]

As a user who has lots of unread items due to losing his history, I agree with this design. Given that currently there is no other way to mark items as read (and I'm not saying there should be), I think it's a good solution.

[Philipp0205]

Can this be merged pls?