Improve library user documentation

At the moment, the user documentation is split into several parts that are sometimes hard to find and sorted according to different principles.

For example, for editing books we have:
1. The editing section in the FAQ (https://openlibrary.org/help/faq/editing#editing-rights)
2. The Librarians Portal (https://openlibrary.org/librarians)
3. The Editing FAQ (https://openlibrary.org/help/faq/editing)
4. The Contribute section (https://openlibrary.org/help/faq/about#contribute)

That means I have to memorize all these places to check if I ever have any question that might fit in either. In some cases, the documentation is even split between Google Docs and the Open Library Webpage.

In some cases, information in different parts of the website even contradicts each other - for example, the Magic Wand to merge authors tells users to select the highest quality profile, the Google Doc explains to use the oldest profile instead.

(Not to mention that the help centre itself is difficult to find, too)

### Describe the problem that you'd like solved

I want a Help Center that leads me toward the answers for my question instead of having to memorize the correct place to lookup a specific question. (I will still memorize the parts I most often need to check, but it would make it easier to find those I only rarely have to consult.)

Ideally, content should be "re-used", that is, being found from different angles so that there is only one description on how to edit books, that can be accessed from different sources.

### Proposal & Constraints

There are several ways to implement such a help centre, and we should check with someone well versed in technical documentation to find the correct approach for open library. This is incredible difficult to get right and also an extremely tedious work.

That being said, for an example on how to organize such a help centre, look at
https://www.cic.gc.ca/English/helpcentre/index-featured-can.asp

I do not think we have the knowledge for this onboard. We need to find someone who specializes in this topic, ideally in a similar way we got Dana and Samuel for improving the UX/UI design. This is probably a long term project, and also requires us to decide on what OpenLibrary primarily wants to be (as discussed during the 2023 mission planning).

### Additional context

This is a problem not only websites struggle with, but also modern video games and large bureaucracies with their detailed norms.

### Stakeholders

Librarians, New Users