Setting memo-type with info of known accounts not working

[ebma]

Stellar-expert introduced a default limit of 10 and a max limit of 200 for their accounts directory request (see here). We'd now need to paginate to fetch all known accounts.
But they also changed the available 'tags'. Now there is only a 'memo-required' tag instead of something like accepts":{"memo":"MEMO_ID"}} so we have to adjust the logic for memos when creating a payment.