[FEATURE] For Enums expose a function that will return a list of all possible constants defined

[alexott]

Problem Statement

In the terraform provider, we may need a validation logic that will check that the value is in the list of all possible constants.

Proposed Solution

For all generated enums generate a function that will return a slice with all defined values for a given type (maybe only string-based types).

Additional Context

See comment here: databricks/terraform-provider-databricks#4051 (comment)