GlColumnChart: Allow customising tooltips
The GlColumnChart component does not expose any way to customise chart tooltips.
We should expose the same slots as other charts to allow overriding the tooltip:
<template v-if="$scopedSlots['tooltip-title']" #title="scope">
<slot name="tooltip-title" v-bind="scope"></slot>
</template>
<template v-if="$scopedSlots['tooltip-content']" #default="scope">
<slot name="tooltip-content" v-bind="scope"></slot>
</template>
<template v-if="$scopedSlots['tooltip-value']" #tooltip-value="scope">
<slot name="tooltip-value" v-bind="scope"></slot>
</template>