Rename remaining article to thread

[melroy89]

Rename all the remaining keywords from article(s) to thread(s). Making the code more consistent.

Which also means I renamed the new valid link for creating a new thread: new/thread in the URL (same for the API).

This PR also finally solves the translation strings that then where still have the key article, articles, edit_article (which was always missing btw), add_new_article, etc. To the new keys: type.thread, thread, threads, add_new_thread and finally edit_thread.

To be backwards compatible with existing data in the database (specifically the type column in the entry table), we keep the article string in the resolveType() function, so t he old string "article" or "articles" are still valid. Same for some Twig templates, we extend with another or for backwards compatibly for now.

The next logical follow-up would be to rename entry as well later.

[BentiGorlich]

Ok I will look at it closer tomorrow. Code wise it looks good now

[melroy89]

Ok I will look at it closer tomorrow. Code wise it looks good now

This pr is less urgent than the 1.7.x fixes. No worries here. It's not really a bug fix.

[melroy89]

Rebased

[BentiGorlich]

@melroy89 do you have an idea why there are so many commits linked to this PR? Doesn't really make sense to me especially since there are multiple commits of other PRs

[melroy89]

@melroy89 do you have an idea why there are so many commits linked to this PR? Doesn't really make sense to me especially since there are multiple commits of other PRs

yeah, I also found this weird. Maybe something went wrong with merging/rebasing?

[melroy89]

I might need to redo this all, and revert several commits via reset hard or something. And try to rebase again. Maybe I started on the main branch initially? And later changed to the new dev/new_features branch?