webadmin : Fixed allignment issues in Hosts General sub-tab

The rows in Hosts General sub-tab were not alligned properly
as each of them were of a different type of label.
ex :
1. TextBoxLabel were generating a input-class for the values.
2. Other labels(inheriting ValueLabel) were generating
   a span tag.
So,this patch makes it uniform by replacing all ValueLabel by
TextBoxLabelBase and its derivatives and hence fixes all the
row allignment issues in Host->General.
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1031596
Change-Id: Iba34398f6972f90d81d76196e060c9184665dd22
Signed-off-by: Anmol Babu <anbabu@redhat.com>