Direct replication with randomly generated objects on source node

[parasj]

Direct replication works with a single direct path.
Test:

$ . scripts/pack_docker.sh && python skylark/test/test_replicator_client.py --copy-ssh-key ~/.ssh/id_rsa.pub --log-dir data/logs/replicate_direct --skip-upload --gateway-docker-image $SKYLARK_DOCKER_IMAGE --n-chunks 32`
2022-01-01 01:26:08.230 | INFO     | __main__:main:80 - Provisioning gateway instances
Provisioning gateways:   0%|                                                                                                                                                                                            | 0/2 [00:00<?, ?it/s]2022-01-01 01:26:35.992 | INFO     | skylark.replicate.replicator_client:provision_gateway_instance:54 - Provisioned gateway i-0878eda586a891987 in us-west-1
Provisioning gateways (aws:us-west-1):  50%|██████████████████████████████████████████████████████████████████████████████████                                                                                  | 1/2 [00:26<00:26, 26.25s/it]2022-01-01 01:26:38.249 | INFO     | skylark.replicate.replicator_client:provision_gateway_instance:54 - Provisioned gateway i-04c1c5cf1be74c04b in us-east-1
Provisioning gateways (aws:us-east-1): 100%|████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████| 2/2 [00:28<00:00, 14.25s/it]
Setting up gateways (aws:us-west-1): 100%|██████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████| 2/2 [00:00<00:00,  3.67it/s]
Starting up gateways (aws:us-west-1): 100%|█████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████| 2/2 [01:43<00:00, 51.63s/it]
2022-01-01 01:28:22.172 | DEBUG    | __main__:main:90 - Source gateway API endpoint: http://18.208.206.255:8080/api/v1
2022-01-01 01:28:22.605 | DEBUG    | __main__:main:91 - Destination gateway API endpoint: http://54.193.221.16:8080/api/v1
2022-01-01 01:28:22.605 | INFO     | __main__:main:92 - Launching replication job
2022-01-01 01:28:27.742 | DEBUG    | skylark.replicate.replicator_client:send_chunk_req:270 - Sending 32 chunk requests to 18.208.206.255

Pertinent URLs:

• Gateway API to control server http://gateway:8080/api/v1
• Docker logs for gateway http://gateway:8888
• Glances UI to monitor utilization http://gateway:61208

[parasj]

@ShishirPatil Merging for now so I can continue to work, but please skim the PR so the design makes sense.