Added missing parameter filterWidgetBuilder and onFilterSuffixTap

[stan-at-work]

This fixes: #121

This adds:

• Missing parameter: filterWidgetBuilder added to customize a pluto column filter.
• Added clearIcon and onClear, if onClear is used then a clear icon shows in the textfield
• Added filterWidgetDelegate, the filterWidgetDelegate is a delegate that has 2 contrcutors.

  /// This is the default filter widget delegate
  const PlutoFilterColumnWidgetDelegate.textField({
    this.filterHintText,
    this.filterHintTextColor,
    this.filterSuffixIcon,
    this.onFilterSuffixTap,
    this.clearIcon = const Icon(Icons.clear),
    this.onClear,
  }) : filterWidgetBuilder = null;

  /// If you don't want a custom widget
  const PlutoFilterColumnWidgetDelegate.builder({
    this.filterWidgetBuilder,
  })  : filterSuffixIcon = null,
        onFilterSuffixTap = null,
        filterHintText = null,
        filterHintTextColor = null,
        clearIcon = const Icon(Icons.clear),
        onClear = null;

Those parameters are removed from the PlutoColumn class and replaced by a filterWidgetDelegate.