rpc: Adjust some `masternode` rpcs (#4060)
rpc: Adjust some `masternode` rpcs (#4060)

* rpc: Deprecate `masternode current` and `masternode winner`

* rpc: Drop deprecated `mode` param in `masternode count`
thelazier/dash,thelazier/dash,dashpay/dash,dashpay/dash,dashpay/dash,UdjinM6/dash,UdjinM6/dash,thelazier/dash,UdjinM6/dash,dashpay/dash,UdjinM6/dash,thelazier/dash,UdjinM6/dash,thelazier/dash,dashpay/dash