ui: Cleanup the navbar "brand"

ui: Cleanup the navbar "brand"

The text shown in the top-left corner of a navbar, known as the "brand"
in Bootstrap parlance, normally brings you to the homepage. However,
when viewing patches or details about a project this name of this
project is included in this link. This gave some users the idea that
clicking this button would return them to the project patch list
instead. To resolve this confusion, break the project name and any
other non-Patchwork title out of this clickable link. A new
"navbar-subnav" style is introduced to do this, seeing as Bootstrap
does not appear to support something like this natively.

Once this is done, this also allows for the removal of the "All
Projects" button, which both duplicates this functionality and did
nothing when there was only one project available on an instance.

Signed-off-by: Stephen Finucane <stephen.finucane@intel.com>