GraphQL API: filtering support in query type definitions

[anggxyz]

Would be great to have filtering support in the GraphQL type definitions.
eg., to filter the result of tokenTransfers according to 'fromAddressHash' and 'toAddressHash'

query getTokenTransfers {
 tokenTransfers (
  	filter: {
      toAddressHash:{
        contains:""
      }
    }
  	first:1
  	after:"YXJyYXljb25uZWN0aW9uOjA="
  	tokenContractAddressHash: "0x2d7882beDcbfDDce29Ba99965dd3cdF7fcB10A1e"
) {
  	edges {
    	  cursor
      	node {
          fromAddressHash
          amount
          toAddressHash
          transactionHash
        }
    }
  	pageInfo{
    		startCursor
      	        endCursor
      	        hasNextPage
  	    }
	}
}