Redis key should be read from Zenroom input

[andrea-dintino]

We need statements like:

Given I read from redis the data under the key named by 'myRedisKey' and save the output into 'redisOutput

Then I write data into redis under the key named by 'myRedisKey'

that reads the input:

{ "myRedisKey": "L1-eth-lastSavedBlock" }