Issue#305: Redesign bridged network UI section

Finished align vlan fields. Redesigned the pattern of the label positions

V3 -> V4:

Address to Hongliang Wang: Assigned "for" attribute for label to associate it with text box accordingly

V2 -> V3:

Address to Hongliang Wang: Have the additional margin place removed.

v1 -> v2:

Address to Hongliang Wang: Have the unrelated lines removed & Have the display format changed from table to div.
Address to Yuxin Huo: Have the unused IDs removed.

Signed-off-by: Wen Wang <wenwang@linux.vnet.ibm.com>