[FEAT]: Add Support for GitHub Enterprise Rulesets

### Describe the need

Currently, the Terraform GitHub provider supports [organization rulesets](https://registry.terraform.io/providers/integrations/github/latest/docs/resources/organization_ruleset) and [repository rulesets](https://registry.terraform.io/providers/integrations/github/latest/docs/resources/repository_ruleset). However, there is no support for rulesets at the enterprise level which GitHub supports on its UI (if you're on the Enterprise plan).

More information around rulesets:
- [About rulesets](https://docs.github.com/en/enterprise-cloud@latest/repositories/configuring-branches-and-merges-in-your-repository/managing-rulesets/about-rulesets)
- [Managing code rulesets for repositories in your enterprise](https://docs.github.com/en/enterprise-cloud@latest/admin/enforcing-policies/enforcing-policies-for-your-enterprise/managing-policies-for-code-governance)

### Code of Conduct

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