Migrate the provider from SDKv2 to plugin framework

The current state of the provider relies on terraform SDKv2 which is now replaced by plugin framework.
We should migrate it following this guide: https://developer.hashicorp.com/terraform/plugin/framework/migrating

Side note: we were using `tflog` which requires to be used with plugin framework. It has made the troubleshooting counter intuitive from @mlcdf when fixing #12 