Add overview page to documentation

[tburny]

The overview page provided users with a map to navigate the documentation while it keeps growing with the project.

While currently there are only two pages (Getting Started and API docs), this is going to change in the near future with further refactorings and improvements to the documentation.

This PR also introduces Diataxis - without imposing a folder structure at the moment to allow for organic growth.

[tburny]

Just FYI: I created the overview page by looking at the Django documentation, which also uses Diataxis. Always good to have a reference.

[oskardudycz]

COMMENT: Later on in Overview, we should probably do more information like I did once in Marten (so what it is and main features) https://martendb.io/introduction.html#what-is-marten.

But this can go as a follow-up.

[oskardudycz]

COMMENT: Maybe we could link those articles here? Thoughts. And tell something along the lines:

You can also find more information about Emmett in those articles. We're working on including all the knowledge centralised in this website.

Then, what you did below.

@tburny, thoughts?

[tburny]

I'd rather keep the overview page concise. My idea would be to have "Further reading sections" at the bottom of the documentation pages that link to the respective blog articles relevant in that context.

As a first step we can have such a section in the overview and migrate them from there.

[tburny]

Just added the link in a "Further reading" section so they are at least somewhere in the documentation.

[oskardudycz]

Makes sense to me, thanks for doing it 👍

[oskardudycz]

@tburny thank you for doing that, I added small comments and suggestions. After they're resolved, I'm more than happy to pull that in.

[tburny]

I implemented the changes as requested (i.e. spelling Emmett correctly). Also I added some minor improvements:

• adding the blog links as "further reading" section and linking to the section from within the "Overview" page
• add links to Discord in the overview page
• There was no way from the landing page to the overview page, so I simply added it to the main nav and made "getting stated" a menu item there. This way new users will probably click the "getting stated" link (call to action), while if I am looking for something else I can still use the menu to roughly navigate to my area of interest (e.g. API reference).

Ready for the second round!

[oskardudycz]

@tburny I think that for now, it makes sense to route people directly to getting started, later on, we can enhance it when we have more content 🙂

Thanks again for sending those docs updates; they are much appreciated!