Add a credential to check is a user has >= a specific number of transactions

[vplasencia]

Description

This PR adds a new provider named blockchain and a new validator named BLOCKCHAIN_TRANSACTIONS with a criteria named minTransactions.

This credential can be used to check if a user has greater than or equal to minTransactions transactions.

There is a new env variable in the api named BLOCKCHAIN_SEPOLIA_RPC_URL. It refers to the sepolia network. If we would like to add a new network, we will only need to add an PRC URL for the network in the api environment variables. Following the structure of BLOCKCHAIN_<NETWORK>_RPC_URL.

The URL for this credential would be:

http://localhost:3001/credentials?group=<group-id>&member=<member-commitment>&provider=blockchain&network=<network-name>&block=<block-number>&redirect_uri=<redirect-url>

The network in the URL should be the same as the one that appears in its RPC URL environment variable inside the api.

The block and the redirect_uri properties are optional.

Related Issue

Closes #369

Does this introduce a breaking change?

• Yes
• No

[0xjei]

Amazing and thank you for introducing the on-chain providers!