Setup ARC GitHub App without org admin permissions

[tbondarchuk]

Here's the way to setup GitHub App for ARC without org admin permissions, just with minor cooperation from an actual admin.

Procedure is following:

1. Request admin to grant your user permission to manage apps

2. Organization's tab 'Settings' now will be available with just a GitHub Apps section

3. Create app following ARC docs, but change the following setting (at the bottom of the page) to Any account - otherwise your user won't see Install option and org admin won't see app at all 🤷

This might be undesired since app will be publicly available, but no sensitive info is exposed as far as I can see.

4. Click Install app which will only create an installation request to admin

5. Ask admin to confirm installation

6. Proceed with rest of ARC docs instructions (get installation ID, etc)

7. Unless you want to setup webhooks in every repo, enable and configure webhook for installed GitHub App and subscribe it to workflow_job events

8. If you wan't to use Runner Groups then you need to ask admin to set them up