Discuss and decide on token airdrop functionality for community vaults

[0x-r4bbit]

Once depositing of tokens into vaults and their migration is done (see: https://github.com/status-im/communities-contracts/issues?q=is%3Aopen+is%3Aissue+milestone%3A%22Community+Vaults+-+Token+Import%22) we need to think about enabling community owners and token masters to airdrop tokens to other accounts.

There's a bunch of ways to make this work. Some of them are:

• Simple transfer
  Basically making a bunch of transactions to a list of addresses. This comes with the downside that the transaction can run out of case, so we need to take into account that the transaction has to happen in batches. Also, the cost is with whomever performs the airdrop (which can get expensive)

• Merkle tree claim
  Instead of sending tokens to a bunch of addresses, the community would have a merkle tree of "white listed" addresses. Accounts can then provide a proof that they're part of the tree, allowing them to claim their tokens.

  This solution requires a bit more upfront computation, but offloads the costs of claiming the tokens to the accounts that is being airdropped to.

@gravityblast @3esmit any other solutions that come to mind? What are their pros and cons?

I personally am in favour of the merkle tree solution.