Related to https://github.com/monero-project/research-lab/issues/78
Added a relay rule that enforces the `unlock_time` field is equal to 0 for non-coinbase transactions.
UIs changed:
* Removed `locked_transfer` and `locked_sweep_all` commands from `monero-wallet-cli`
APIs changed:
* Removed `unlock_time` parameters from `wallet2` transfer methods
* Wallet RPC transfer endpoints send error codes when requested unlock time is not 0
* Removed `unlock_time` parameters from `construct_tx*` cryptonote core functions
@tobtoht: undo rebase changes tx.dsts -> tx_dsts
When RingCT is enabled, outputs from coinbase transactions
are created as a single output, and stored as RingCT output,
with a fake mask. Their amount is not hidden on the blockchain
itself, but they are then able to be used as fake inputs in
a RingCT ring. Since the output amounts are hidden, their
"dustiness" is not an obstacle anymore to mixing, and this
makes the coinbase transactions a lot smaller, as well as
helping the TXO set to grow more slowly.
Also add a new "Null" type of rct signature, which decreases
the size required when no signatures are to be stored, as
in a coinbase tx.
