add datasource for each resource

[rucciva]

Current Terraform Version

Terraform v1.5.4
on darwin_amd64

Use-cases

we are currently managing the huaweicloud resources using the web console. Our team has not yet ready to fully manage them using terraform, but we are currently trying to use terraform to backup the resource configuration mainly using data source and saving them to yaml files commited to git. This unfortunately can't be fully functional since not all resource on huawei cloud has data source, e.g. waf' website, private nat gateway, and several. We also need the data source that can return all resources, similar to huaweicloud_vpcs

Attempted Solutions

Proposal

Create all data source for each resource including data source that can returns all resource, similar to huaweicloud_vpcs

References