Remove all of the namespace level rollout flags and replace them with a single taskworker.rollout option. The default value of the option should be True.

• Add the new option, update the code path that produces activations and remove reads from the namespace options.
• Update self-hosted configuration to disable taskworker.rollout until we can validate that self-hosted works correctly and we've published documentation on how to operate the new system.
• Remove option data for the namespace rollouts.