Add the Contao.org top-navigation to the docs

[contaoacademy]

The top navigation as seen on contao.org should also be visible in the doc.
Task for @fritzmg

[fkaminski]

Should the links be adopted 1 to 1? Some could be neglected here (Docs, Login). Perhaps Contao social media links should be given priority here?

[fritzmg]

Should the links be adopted 1 to 1

Yes it is a generalized script. Adjusting it is not worth it and imho for consistency it should stay the same everywhere anyway.

[fkaminski]

Understood! But I still think our social media links are not unimportant (they are currently only listed here).

Perhaps we could add them in the footer (with icons only)?
I could extend the PR #1354 accordingly ...

[netzarbeiter]

I don't want to add social media links ony every single docs page, this is enough.