widen active area for triggering of column resizing pointer

[sfinktah]

tl;dr -- it's very finicky to get the pointer in the right place to engage column resizing.

solution:

    createResizableBar(height) {
// ...
      div.style.right = '-6px';
      div.style.width = '12px';
// ...
      return div;
    },

side effect: creates an unwanted 6px padding to the right of the table. can be countered by css, which i have only partially included in scss as i am not sure the second is necessary or desirable.

table.table.resizable-resource-table > thead > tr > th:last-of-type::after {
    width: 0;
}

table.table.resizable-resource-table > thead > tr > th:last-of-type > div {
    display: none;
}