Implement custom criticality sorting

[opauloh]

Motivation

This ticket aims to pass custom column schema and schema detector to the UnifiedDataTable component, which will allow custom sorting text capability on the UnifiedDataTable column headers. Currently, the sorting text is dynamically identified by the UnifiedDataTable plugin, and we want to be able to pass custom sorting.

Use cases:

One use case is to allow changing the Criticality column sorting of the Inventory page to sort by Criticity, i.e: (Critical -> High -> Medium -> Low) instead of Alphabetical (which currently leads to (Critical -> High -> Low -> Medium)).

Definition of done

• UnifiedDataTable accepts customSchemaConfig and the columns object accepts a schema property.
• The column schema can be pointed to the customSchemaConfig.
• When not override the field sorting is dynamic calculated.
• The Asset Inventory datagrid uses the custom criticality sorting
• Unit tests are written to ensure the default functionality works alongside the schema override

[elasticmachine]

Pinging @elastic/kibana-cloud-security-posture (Team:Cloud Security)