About:
    An Ockam Authority node is an Ockam node running a limited set of services used by other nodes to:
        - issue credentials
        - create enrollment tokens
        - accept enrollment tokens
        - authenticate identities as project members

    Those services are accessible by creating a secure channel over a TCP connection at `tcp-listener-address`.

Examples:
```sh
    # Create an authority node which can be accessed by users of project 93c6455c5f
    # The default node name is 'authority'.
    $ ockam authority create \
          --tcp-listener-address 127.0.0.1:4200 \
          --project-identifier 93c6455c5f \
          --trusted-identities "[{\"identifier\": \"P6c20e814b56579306f55c64e8747e6c1b4a53d9a3f4ca83c252cc2fbfc72fa94\", \"attributes\": {\"ockam-role\": \"enroller\"}}]"

    # Create an authority node which can be accessed by users of project 93c6455c5f
    # Trusted identities come from a file which is always reloaded where searching for an identity attribute
    $ ockam authority create \
          --tcp-listener-address 127.0.0.1:4200 \
          --project-identifier 93c6455c5f \
          --reload-from-trusted-identities-file trust-anchors.json

    # Delete an authority node
    $ ockam node delete authority
```
