Add codemeta generator to navbar

[tmorrell]

The codemeta generator is awesome and already hosted on the site. We should link to it from the navbar so people can find it easier.

[bact]

We have a "Create" link on the navbar that link to this page https://codemeta.github.io/create/ and that page has the link to CodeMeta Generator.

Or we need a direct "CodeMeta Generator" link on the navbar?