feat: bind event item to timeline custom connector slot

[robbienohra]

Currently, style overrides to the timeline connector component happen globally at the timeline component level. It is not an uncommon use case to require dynamic style overrides across multiple connectors for a given timeline instance. This can be achieved (as is being done with the marker and content named slot) by binding the item property to the connector named slot. This enables the following type of customization to connectors for a given timeline.

<template #connector="slotProps">
            <div
              class="p-timeline-event-connector"
              :style="{ width: '4px', backgroundColor: slotProps.item.color }"
            ></div>
</template>

Unless there is a strong reason to not support this (can't see what that reason would be) I think this would be a really useful addition to the component!

[robbienohra]

Created an issue here to follow the recommended repo process.