[Visualizations] Value mapping or display alias names for fields in Kibana

[vinaydhegde]

Describe the feature:
In the Visualization panels, We need an easy way to configure value mapping or set alias names for the field values.
See the screenshot below. Here, the value of 'k8s.pod.phase' field can be 1 or 2 or 3 or 4. If we need to represent it with meaningful status value, there is no easy way out (like setting alias names)

Describe a specific use case for the feature:
Off course, we can create a custom/Runtime fields like below, to achieve this. But it is not simple & it's hard to mantain.

For Boolean or integers values, translating them to some meaningful values is not easy.
For example, k8s.pod.phase field can have a value between 1 to 4.
1 -> Pending, 2 -> Running
3 -> Succeeded 4 -> Failed

[elasticmachine]

Pinging @elastic/kibana-visualizations (Team:Visualizations)