Upgrade to bulma 0.6.2.

This includes additional changes for this work properly.

* The old style nav in the hero is changed to the new navbar approach.
 * `nav-left` block is now located in nav-brand
   This is sematically wrong but this way the name stays the same.
 * `nav-right` block is now located in nav-end
   This is sematically wrong but this way the name stays the same.
 * We now a mobile menu together with proper js for collapse and expand.
 * The ssoauth template by default loads the auth header in nav-right