fix(columns): don't reset resized columns on data reset by default

[SomeKittens]

Previously, if a user resized a column and the data were reset, the column size would also be reset. Instead, disable this behavior by default and add a flag (allowCustomWidthOverride) to allow it. Code originally taken from mage-eag@966c4d9

Fixes #4005

[swalters]

@c0bra @PaulL1 would you guys also take a look at this. It looks good to me, other than we probably need to document this new flag.

[cedejic]

Hi,

I may be wrong, but I believe you should also set column's hasCustomWidth property in uiGridSaveStateService::restoreColumns. So when you load state from e.g. database columns would set up properly.

              if ( grid.options.saveWidths ){
                currentCol.width = columnState.width;
                currentCol.hasCustomWidth = true;
              }