Fix NavBar width
Fix NavBar width

Fix the issue with the navbar providing only the same
amount of width as the characters representing it. It
should size to the width of the items contained within
it instead.

Closes #10386

SudiptaBiswas/moose,dschwen/moose,laagesen/moose,friedmud/moose,milljm/moose,milljm/moose,bwspenc/moose,idaholab/moose,idaholab/moose,andrsd/moose,bwspenc/moose,laagesen/moose,YaqiWang/moose,SudiptaBiswas/moose,idaholab/moose,bwspenc/moose,SudiptaBiswas/moose,nuclear-wizard/moose,nuclear-wizard/moose,milljm/moose,jessecarterMOOSE/moose,permcody/moose,friedmud/moose,sapitts/moose,milljm/moose,sapitts/moose,SudiptaBiswas/moose,dschwen/moose,permcody/moose,permcody/moose,jessecarterMOOSE/moose,laagesen/moose,jessecarterMOOSE/moose,friedmud/moose,bwspenc/moose,YaqiWang/moose,milljm/moose,YaqiWang/moose,lindsayad/moose,bwspenc/moose,sapitts/moose,dschwen/moose,nuclear-wizard/moose,sapitts/moose,harterj/moose,andrsd/moose,lindsayad/moose,idaholab/moose,andrsd/moose,SudiptaBiswas/moose,jessecarterMOOSE/moose,dschwen/moose,nuclear-wizard/moose,dschwen/moose,lindsayad/moose,permcody/moose,harterj/moose,jessecarterMOOSE/moose,idaholab/moose,laagesen/moose,sapitts/moose,YaqiWang/moose,friedmud/moose,harterj/moose,laagesen/moose,lindsayad/moose,lindsayad/moose,andrsd/moose,andrsd/moose,harterj/moose,harterj/moose