eosio.erc2o contract implementation

[taokayan]

Resolves #612, based on @yarkinwho 's work.

list of actions:

• upgrade: deploy the implementation contract on EVM side
• regtoken: deploy and initialize the proxy contract on EVM side with parameters (symbol, precision... etc), setup the linkage between EOS token contract and EVM ERC-20 contract.
• transfer(notifier): implemention of EOS token->EVM ERC20 bridging
• onbridgemsg: implementation of EVM ERC20 -> EOS token
• addegress: add white list to accounts with contracts
• removeegress: remove white listed accounts;

example commands:

echo "=== deploy eosio.erc2o contract & register bridge ==="
./cleos set code eosio.erc2o ~/workspaces/evm-bridge-contracts/erc20.wasm
./cleos set abi eosio.erc2o ~/workspaces/evm-bridge-contracts/erc20.abi
./cleos push action eosio.evm bridgereg '["eosio.erc2o","eosio.erc2o","0.0100 EOS"]' -p eosio.erc2o -p eosio.evm@owner
./cleos transfer a123 eosio.evm "100.0000 EOS" "eosio.erc2o"
./cleos set account permission eosio.erc2o active --add-code

echo "=== link USDT EVM bridge (usdt <==> 0x4ea3b729669bf6c34f7b80e5d6c17db71f89f21f) ==="
./cleos push action eosio.erc2o upgrade '[]' -p eosio.erc2o

./cleos push action eosio.erc2o regtoken '["usdt","EVM USDT Token","WUSDT","0.0100 USDT","0.0100 EOS",6]' -p eosio.erc2o

echo "=== the USDT-ERC20 contract should be 3a13a4653761299d8b9d0d5dcac100d0c961938b ==="

echo "=== transfer USDT (EOS->EVM) ==="
./cleos get currency balance usdt usdt
./cleos transfer usdt eosio.erc2o "1000.0000 USDT" "0x2787b98fc4e731d0456b3941f0b3fe2e01439961" -c usdt
./cleos get currency balance usdt usdt

echo "=== call bridge Transfer (EVM 0x278...->EOS a123) 12 USDT to account ==="
python3 ./send_data_via_cleos.py 0x2787B98fC4e731d0456b3941f0B3fe2e01439961 0x3A13A4653761299D8b9D0D5DCaC100D0c961938B 10000000000000000 73761828000000000000000000000000bbbbbbbbbbbbbbbbbbbbbbbb30443000000000000000000000000000000000000000000000000000000000000000000000b71b000000000000000000000000000000000000000000000000000000000000000060000000000000000000000000000000000000000000000000000000000000000f6b6179616e6b6179616e6b6179616e0000000000000000000000000000000000 3

echo "=== a123 now should have some USDT ==="
./cleos get currency balance usdt a123

[arhag]

Make sure tests work with other token symbol names other than USDT (and also other precisions).

[arhag]

Also needs more tests with different symbol names and precisions (including greater precision for ERC20 than native token). As well as testing the various limits on amounts that are being enforced in the code.

[arhag]

Also:

• Add action to change ingress fee. (Action to change egress fee does not have to happen in this PR and is tracked by Change egress fee for registered token #9.)
• Properly account for the accumulated received ingress fees in the table for the registered token. (Action to withdraw these fees does not have to happen in this PR and is tracked by Action to withdraw collected fees for registered token #10.)

[taokayan]

Also:

• Add action to change ingress fee. (Action to change egress fee does not have to happen in this PR and is tracked by Change egress fee for registered token #9.)
• Properly account for the accumulated received ingress fees in the table for the registered token. (Action to withdraw these fees does not have to happen in this PR and is tracked by Action to withdraw collected fees for registered token #10.)

Done

[arhag]

Unit tests are still light and even those need to be fixed. See my comment from #5 (review). The only issue is can you do any of these tests without bringing in the actual EOS EVM Contract. If so, that's more of an integration test which is tracked by #12.

[yarkinwho]

Need to call bridgereg() somewhere

and record the receiver in the table. receiver should be part of the unique key as well.

[yarkinwho]

Sol contracts needs some modification.