[pgAdmin4][Patch]: RM#1243 - Columns on the Query Tool should be sizeable

Hi

Added support for *Columns resizable in query tool*. It allows user to
resize the table columns as much as needed.

We are using Backgrid Sizeable Columns plugin:
*https://github.com/WRidder/backgrid-sizeable-columns
<https://github.com/WRidder/backgrid-sizeable-columns>*

with one change in library on line no 185:
moved the following trigger event out of *if condition*:

if (newWidth != oldWidth) {

}

and added one additional parameter *offset*.
//Trigger event

view.columns.trigger("resize", columnModel, newWidth, oldWidth, offset);

We are listening to this trigger event in *sqleditor.js* file where we need
*offset*
to calculate new table width on every resize event.

hence, here is the patch attached.

Please review.

Thanks,
Surinder Kumar