webadmin: adding '...' appender to text columns that overflow

Using TextOverflow.ELLIPSIS style property to achieve this.

Change-Id: Ibabe4f05b92f0f448207fb08700b75afed645de7
Bug-Url: https://bugzilla.redhat.com/1122990
Signed-off-by: Alona Kaplan <alkaplan@redhat.com>