terraform-provider-vultr: Update to version 2.29.1 and convert to terraform/provider.mk

Packaged in wip by iquiw, thanks!

pkgsrc changes:
- Adapt to terraform/provider.mk so that the provider can be used with
  Terraform and OpenTofu.
  Please note that now it no longer depends on terraform or opentofu so
  the desired version should be manually installed.

Changes:
- Resource / data sources improvements and syncing with what Vultr provides
- Bug fixes
- Dependencies updates
