Expand coretime management functionality for sudo ops

[seadanda]

#4273 introduces a mechanism to quickly reserve a (usually system) workload.

We should build an expanded set of functionality for managing the network's coretime allocations without needing to dabble with migration+runtime upgrade or set/kill storage patterns as we've done in the past.

This can be for governance on production networks or for managing testnets, especially those where the token has no intrinsic worth.

Here is some example functionality:

• onboard a system workload immediately overriding whatever is on that core (force_reserve) [pallet-broker] add extrinsic to reserve a system core without having to wait two sale boundaries #4273
• remove a lease
• remove an assignment from the Workplan
• add an assignment to the Workplan
• remove a PotentialRenewal
• add a PotentialRenewal
• reset the base/min price - h/t to the recent Kusama ref, this should be supported cleanly if people want to do it for some reason in the future, and is nice to have for testnets
• Force transfer a region, ignoring the owner