[FEATURE] Add support for Primary and Foreign Key Constraints in databricks_sql_table

[hshahconsulting]

Use-cases

I would like to use the Primary Key and Foreign Key feature that is generally available in Databricks to view relations between keys in columns when browsing tables in the Unity Catalog.

https://www.databricks.com/blog/primary-key-and-foreign-key-constraints-are-ga-and-now-enable-faster-queries

Proposal

resource "databricks_sql_table" "my_table" {
	name               = "bar"
	catalog_name       = "main"
	schema_name        = databricks_schema.this.name
	table_type         = "MANAGED"
	properties         =  {
		this      = "that"
		something = "else"
	}

	column {
		name      = "id"
		type      = "bigint"
	}
	column {
		name      = "name"
		type      = "string"
	}
	column {
		name      = "externalId"
		type      = "string"
	}
	key_constraint {
		primary_key = "id"
	}
	key_constraint {
		referenced_key = "external_id"
		referenced_catalog = "bronze"
		referenced_schema = "biz"
		referenced_table = "transactions"
		referenced_foreign_key = "transactionId"
	}
	comment = "this table is managed by terraform"
	owner = "account users"
}