feat: add option to use PAT to register runners on enterprise level

[pharindoko]

Currently it`s only possible to register runners on repository level using the PAT option.
And via github app it`s only possible to do this on repo or org level.

I would like to be able to register runners on enterprise level using GHES.

You can set in the pat permissions the option to

• manage_runners:enterprise | Manage enterprise runners and runner groups
  This would give us new opportunities to use the runners at scale and simplify the management.

[kichik]

I'm open to it, but don't have GHES to test.

[kichik]

How do you register runners on the enterprise level with API? I can only see API for organization registration that can take a token with manage_runners:enterprise.

[pharindoko]

Haven`t registered a runner yet on enterprise level. As far as I`ve read this should work ... https://docs.github.com/en/enterprise-server@3.9/actions/hosting-your-own-runners/managing-self-hosted-runners/adding-self-hosted-runners#adding-a-self-hosted-runner-to-an-enterprise

[kichik]

Seems like this is the API we were looking for.