Vaulta transition

[nsjames]

This PR shuts off the ability to deposit, withdraw, unstaketorex, and claimrewards with EOS directly. You will need to now go through core.vaulta to be able to interact with those actions.

It also updates the eosio.bpay contract's claimrewards action to swap the EOS in its control to $A before sending it to the claimer.

[greg7mdp]

I'm not sure I understand the relationship of this contract vs system.entry in xyz-system-contracts repo? It looks like mostly the same code. Is core.vaulta going to replace system.entry?
I thought the conversion EOS to A had already started using system.entry? Will the system.entry supply of A be transfered to core.vaulta?

[nsjames]

I'm not sure I understand the relation of this contract vs system.entry in xyz-system-contracts repo? It looks like mostly the same code. Is core.vaulta going to replace system.entry? I thought the conversion EOS to A had already started using system.entry? Will the system.entry supply of A be transfered to core.vaulta?

The contract here is the bare minimum parts of the real core.vaulta contract required to test the changes for staking and the 2 claimrewards actions. There's going to be a subsequent PR that merges in all of the core.vaulta code as well as the tests there, and fixes the rest of the tests here to work with core.vaulta.