feat(log) logs the authenticated consumer

[subnetmarco]

Full changelog

• Logging plugins now also log the authenticated consumer

[Tieske]

Maybe some tests? with auth that has a consumer as well as with auth that doesn't have a consumer (like ldap)

[subnetmarco]

with auth that has a consumer as well as with auth that doesn't have a consumer (like ldap)

I would expect the consumer to be nil, and therefore the property to be missing (like it happens one line above with the API object for example).

[Tieske]

I would expect that to, but a test would be the prove of that.

[thibaultcha]

Those tests are fine for now, but ideally crucially lack integration tests, ensuring that we are correctly setting ngx.ctx.authenticated_consumer. This is especially important in such dynamic languages that are so vulnerable to typos, as proven times and times again. Will squash and merge.