webadmin: Enable column resizing in Network main tab

1. Enabled column resizing in Network main tab table,
   to keep it consistent with other table-based main
   tabs

2. Removed maxTextLength restriction since the column
   resizing makes it unnecessary (the user can simply
   resize the column)

Change-Id: Ib89d494a26a7fb48a5525057ab89e86f2ac07ad6
Signed-off-by: Vojtech Szocs <vszocs@redhat.com>