[FEAT]: Data Source with Owner/Organization/Enterprise Context

### Describe the need

We can use the following to get context about the currently authenticated user:

```terraform
data "github_user" "_" {
username = ""
}
```

It would be great to be able to get information about the current owner/organization/enterprise such that it can rely on the current authentication context to determing if the `GITHUB_OWNER` is an organization or enteprise.

This can be useful for variable validation when specific arguments or nested blocks can only be used in a certain context, like the `branch_name_pattern` nested block in the `github_repository_ruleset` resource.

### SDK Version

_No response_

### API Version

_No response_

### Relevant log output

```shell
N/A
```

### Code of Conduct

- [x] I agree to follow this project's Code of Conduct