Config: Add navbar link to apps/home

[cassidyjames]

Not 100% sure what the right copy is here but I've also been annoyed it's not simple to click to get back over to flathub.org.

Alternatively, we could make the logo itself link to https://flathub.org, and change the Publish link on the home page to point to https://docs.flathub.org or something, but I think this is fine to start.

Fixes #244

[razzeee]

the right copy? Do you mean naming?

I do like the logo idea, but it might also be confusing.

[cassidyjames]

@razzeee yeah idk if we want to call it “apps,” or “home,” or what. 🤷

[razzeee]

Store? Not sure we will find a name that makes us happy. Especially for the header, might actually be easier in the footer.

[razzeee]

Coming back here, I still like Store I guess.