Trim uids

[unconst]

Description

Allows subnets to trim the number of active UIDs while preserving immune UIDs (temporally and owner owned), compressing the UIDs to the left and migrating/clearing associated storage.

A new extrinsic + storage item has been defined for the minimum allowed number of UIDs of a subnet and we can't trim below this limit which is set to 64 to start with and will allow gradual controlled trimming on a per subnet basis to prevent abuse.

[ales-otf]

Confused about these "UID's". At first glance it looks like a hyperparameter. If so, you need to extend the Hyperparameter enum we introduced earlier and use TransactionType::OwnerUpdateHyperparam. You would also need to use ensure_root_with_limits to enforce the freeze window. Otherwise just ignore. At the same time I can see it was before and it's configured via a constant.

[l0r1s]

Confused about these "UID's". At first glance it looks like a hyperparameter. If so, you need to extend the Hyperparameter enum we introduced earlier and use TransactionType::OwnerUpdateHyperparam. You would also need to use ensure_root_with_limits to enforce the freeze window. Otherwise just ignore. At the same time I can see it was before and it's configured via a constant.

Yes, it is like an hyperparameter but with a custom rate limit of 1 time per month to avoid abuse given it kicks out neurons.

I added the ensure_root_with_limit for the 2nd extrinsic!