Added optional params for header navbar
Added optional params for header navbar

Change-Id: I682236f6b2b39f8e7e5f57e7e8bbbbfe817f4cb7
Signed-off-by: Martin Lowe <504e0a986396988ebec7c1694a265845da548725@eclipse-foundation.org>

EclipseFdn/solstice-hugo-theme,EclipseFdn/solstice-hugo-theme