Disable anonymous access in accordance with new orga setting

[luisa-beerboom]

See OpenSlides/openslides-client#4204 and OpenSlides/openslides-backend#2656

There is going to be a new setting organization/enable_anonymous.
As long as that is not turned on, all meetings should be restricted as if meeting/enable_anonymous is turned off.

I.e. if enable_anonymous is false for the organization, anonymous users should not be able to see a single meeting (or much of anything else for that matter), even if some are published. The anonymous feature should effectively be disabled.

[luisa-beerboom]

Meta PR is OpenSlides/openslides-meta#177