Minting NFT by attestation when type of ticketID is string

[oleggrib]

few month ago we updated ticket schema to allow ticketId as string. #221

so new tickets can be passed for minting to the SmartContract. so we need updated validationContract to allow string if someone use ticketId as string. For compatability we can return numbers as strings too. @JamesSmartCell, cound you update validation contract?

currently we can use existing contract and dont let users to use ticketID as string, so it will not affect current projects

Current smartContract logic: NFT_ID = ticketID + OpenZeppelin enumerable, but I am going to update it.

• NFT_IDs will be increasing
• I will add relation NFT_ID->ticketId
• optimized enumeration

@AW-STJ , @nicktaras