add create mint entitlement json sample

[elv-todd]

for https://github.com/qluvio/elv-apps-projects/issues/243

$ node samples/GenMintEntitlement.js iten4TXq2en3qtu3JREnE5tSLRf9zLod iq__2dXeKyUVhpcsd1RM6xaC1jdeZpyr C9Zct19CoEAZYWug9tyavX 1 nonce_6f9f53ecc09a7e223cf7d47f pid_e852572c6e84626892da049
SIGNER 0x761f45287ea364db6b216bd655910430afa3e839
ENTITLEMENT TO SIGN {"tenant_id":"iten4TXq2en3qtu3JREnE5tSLRf9zLod","marketplace_id":"iq__2dXeKyUVhpcsd1RM6xaC1jdeZpyr","items":[{"sku":"C9Zct19CoEAZYWug9tyavX","amount":1}],"nonce":"nonce_6f9f53ecc09a7e223cf7d47f","purchase_id":"pid_e852572c6e84626892da049"}
ENTITLEMENT {
  tenant_id: 'iten4TXq2en3qtu3JREnE5tSLRf9zLod',
  marketplace_id: 'iq__2dXeKyUVhpcsd1RM6xaC1jdeZpyr',
  items: [ { sku: 'C9Zct19CoEAZYWug9tyavX', amount: 1 } ],
  nonce: 'nonce_6f9f53ecc09a7e223cf7d47f',
  purchase_id: 'pid_e852572c6e84626892da049'
}
ENTITLEMENT_SIGNATURE ES256K_7uAQCp6nUQDiyHUSUa4AHV91rTpgoUsRQ4pPrjZpY9PZ3Ww21ZFaF4q6zXKP2TFQajbvUMS38PGeyA6XERwpcasbh
ALL DONE

[elv-todd]

updated to use new sig format:

$ node samples/GenMintEntitlement.js
SIGNER 0x761f45287ea364db6b216bd655910430afa3e839
ENTITLEMENT {
  tenant_id: 'iten4TXq2en3qtu3JREnE5tSLRf9zLod',
  marketplace_id: 'iq__2dXeKyUVhpcsd1RM6xaC1jdeZpyr',
  items: [ { sku: 'C9Zct19CoEAZYWug9tyavX', amount: 1 } ],
  nonce: 'nonce_6f9f53ecc09a7e223cf7d47f',
  purchase_id: 'pid_e852572c6e84626892da049a'
}
ENTITLEMENT_SIGNATURE mje_2LDb4upTtBDeQdcAt2oBvya1338s3WVdrzCQZFvXo1YLiAmWvh44xAZcdpJyzhtcuG4s6PNXgcBYbfrbAPxNK3bYEUYkv9Pp6uHGvvP8V8f5bPDk6qMYvYCvH94AsrxhqXY3Gsn98uTNioe6711ZFpQTBjDukL4Xt7mzvN88NvxU5oWCV2W1vzn1VPnPrVZZ6TSkv4fLTHj1bJfL5NWSgDBAcQYAf9pdNgiJX9reYQGKceQk5LViqNfjSBXhzd4rgbvBJMD8Uua8mXo1zqxCoyZrR5UhfvpsNX3oSd9P8Vw5zVDNX3s9JpPR8edZ73EbZixoiYf5h6bJfZggHJDxcgkzzD5Unhcbz3MxA7XS6yZ32A1dsXfWtc1m2AQU1vLEmoyr9oQG9JCURznZhFtHGR4qhieBnWMZN
ALL DONE

[elv-serban]

I think this is fine to merge and then modify to use a more official elv-client-js CreateSignedMessageJSON once we have one

[elv-serban]

I would remove the comments referencing the names of test tenants and marketplaces. It's fine to leave the IDs as examples.