Allow applications to opt-in to precisely defined propagation delays

[erkinalp]

The problem

Currently, slash and context menu commands take up to an hour to propagate, and repaired on attempt to access.

The proposed solution

It would be far easier to make planned API transistions if this if newly created commands and new changes to commands left disabled until exactly 3600 seconds after registering/changing/deleting the command, even if they completed propagating earlier.

Extra considerations

To allow applications to choose between quick deployment and deterministic propagation delay, this should be opt-in.