Provide a programmable way to register a new action runner

[yardenshoham]

Feature Description

I wish there was an API endpoint I could query to retrieve a token I could register a new runner with. Currently, the only way to do this is to go to the web UI and copy the token from the page.

[wolfogre]

I remember I have discussed it with Lunny privately before, and the consensus is providing reusable token to register multiple runners, or you still need an auth token to use API.

Or we can provide reusable token to register multiple runners when you need an API auth token which can only obtain tokens to register runners.

Reusable tokens are feasible both in design and technology, you can even do this by modifying the status of tokens in database manually.

[wolfogre]

To be clear, I have no objection to having API to manage runners like listing, registering and removing.