Add vcfa_org_vdc resource and data source + vcfa_region_zone data source

[adambarreiro]

Adds vcfa_org_vdc resource and data source and required data source vcfa_region_zone

Refs:

• VDC resource and datasource, Region Zone data source terraform-provider-vcd#1350

[Didainius]

Quick scan

[lvirbalas]

@Didainius FYI, hitting one intermittent (unrelated to this PR) issue while running the tests:

=== RUN   TestAccVcfaVcenterInvalid
    resource_vcfa_vcenter_test.go:194: Step 2/2 error: Error running post-apply refresh: exit status 1

        Error: error executing read Tenant Manager vCenter Server hooks: error executing hook: error refreshing Storage Policies: error waiting task completion: task did not complete successfully:  [400:BUSY_ENTITY] - [ 1129-2025-01-23-09-16-38-169--5f357720-9e25-4944-92b3-d2d021bd921a ] The entity vCenter Server is busy completing an operation TestAccVcfaVcenterInvalid.

          with vcfa_vcenter.test,
          on terraform_plugin_test.tf line 24, in resource "vcfa_vcenter" "test":
          24: resource "vcfa_vcenter" "test" {

--- FAIL: TestAccVcfaVcenterInvalid (405.28s)