Proxy contract: Balance of vested and unvested tokens

[Edd]

Note: This is an acknowledged 'bit of a hack' and is not essential or blocking anything. But if it's a success, it'll slightly improve the the lives of people wondering how many VEGA tokens they have in V2 across all tranches

Goal

A user of Metamask / other wallet should be able to add this token address and see their balance as the sum of their token balance in all tranches

Example 1: tokens in tranches

• 0xedd has 10 tokens in tranche 0
• 0xedd has 10 tokens in tranche 1
• 0xedd on the new proxy contract has a balance of 20 tokens

Example 2: Edd has redeemed tokens in tranches

• 0xedd has redeemed all 10 tokens in tranche 0
• 0xedd has 10 tokens in tranche 1
• 0xedd on the new proxy contract has a balance of 10 tokens

Tasks

• Add a new ERC20 token on Ropsten that represents the total balance an address has across all tranches of the vesting contract

Notes

• For testing purposes, tranche 0 should already exist and can have tokens allocated to it

• Vega_Token_V2/contracts/ERC20_Vesting.sol

  Line 98 in 0838503

   function create_tranche(uint256 cliff_start, uint256 duration) public only_controller { 

  can be used to create new tranches
• This is expected to be quick, and imperfect. If it takes more than a few days, it's not worth the hassle. If it works but isn't nice, we'll never tell anyone about it
• Users will not be able to transfer balances. This contract only represents balances

Slack ref: https://vegaprotocol.slack.com/archives/CMVDT0ZU6/p1626095691384100?thread_ts=1626091258.380400&cid=CMVDT0ZU6

cc @C0deMunk33 / @MM0819 / @barnabee

[Emil Bay]

Code for this now lives here until we decide whether it is worth deploying on mainnet: https://github.com/vegaprotocol/vega-erc20-proxy