Slider tooltip should be configurable

[pmiklashevych]

https://www.bryntum.com/docs/calendar/#Core/widget/Slider#config-tooltip

It's hardcoded in constructor

        if (me.showTooltip) {
            me.tip = new Tooltip({
                forElement : me.input,
                anchor     : false, // No anchor displayed since thumbSize is different for different themes
                align      : 'b-t',
                axisLock   : true
            });
        }