[Feature] Load some data to ETCD instances in every e2e tests

[abdasgupta]

Feature (What you would like to be added):
Load a considerable amount of data to the ETCD instances that we create for each e2e tests
Motivation (Why is this needed?):
Currently, we are spawning single node or multi node ETCD cluster in our e2e tests based on the spec. But those ETCDs are empty ETCD and may not test the actual ETCD in action completely. So, the proposal is to generate a considerable amount of random data, load the data into ETCD once the ETCD nodes are initialized. Then perform the other e2e test steps on them. Only con is that the tests may take longer to complete.
Approach/Hint to the implement solution (optional):