Entityframework.docs: Remove Layer - 2 (L2) .NET navigation header

[wadepickett]

A new navigation header has been already published for all docs.microsoft.com It duplicates items already in the .NET layer 2 navigation header. We are removing the .NET layer 2 navigation header across all published dotnet content repos.

• Remove the L2 .NET Header from docfx.json

Also reviewed:

• Do we add a "Download .NET" and/or Community link to the EF Hub page or elsewhere?
  Conclusion: Do not include them.

[wadepickett]

@JeremyLikness, does this proposal sound good to you? The L2 Navigation that I am referring to is the ".NET About Learn Docs Downloads Community" navigation layer at the top of all the EF content

[JeremyLikness]

I don't see a lot of community clicks and "download .NET" feels out of place on the Entity Framework Core hub. I recommend we just remove L2 navigation.

[JeremyLikness]

Pinging @ajcvickers for his thoughts.

[ajcvickers]

Agree with @JeremyLikness