ec2-resource-agent: deregister as ECS instance before termination

[etungsten]

Before we terminate the EC2 instance, if the instance was previous registered as a ECS container instance, kick off ECS container instance deregisteration before terminating the EC2 instance.

Issue number:
Resolves #717

Description of changes:

    ec2-resource-agent: deregister as ECS instance before termination
    
    Before we terminate the EC2 instance, if the instance was previous
    registered as a ECS container instance, kick off ECS container instance
    deregisteration before terminating the EC2 instance.

Testing done:

EC2 resource agent for ECS clusters delete cleanly and ensures all ECS container instances are de-registered with a 5 min timeout that doesn't error and proceeds to terminate the EC2 instance.

[2022-12-20T02:41:23Z INFO  resource_agent::agent] Initializing Agent
[2022-12-20T02:41:23Z INFO  ec2_resource_agent::ec2_provider] Kicked-off ECS instance deregistration for 'arn:aws:ecs:us-west-2::container-instance/aarch64-aws-ecs-1-nvidia/bcdc114aa81f4b3eb0287b0a6a
c8360b'
[2022-12-20T02:41:23Z INFO  ec2_resource_agent::ec2_provider] Kicked-off ECS instance deregistration for 'arn:aws:ecs:us-west-2::container-instance/aarch64-aws-ecs-1-nvidia/1dcbd507512149e2ae86aa71fc
801db1'
[bottlerocket/agents/src/bin/ec2-resource-agent/ec2_provider.rs:657] listed_instances = [
    "arn:aws:ecs:us-west-2::container-instance/aarch64-aws-ecs-1-nvidia/1dcbd507512149e2ae86aa71fc801db1",
    "arn:aws:ecs:us-west-2::container-instance/aarch64-aws-ecs-1-nvidia/bcdc114aa81f4b3eb0287b0a6ac8360b",
]
[bottlerocket/agents/src/bin/ec2-resource-agent/ec2_provider.rs:658] container_instances = [
    "arn:aws:ecs:us-west-2::container-instance/aarch64-aws-ecs-1-nvidia/bcdc114aa81f4b3eb0287b0a6ac8360b",
    "arn:aws:ecs:us-west-2::container-instance/aarch64-aws-ecs-1-nvidia/1dcbd507512149e2ae86aa71fc801db1",
]
...
[bottlerocket/agents/src/bin/ec2-resource-agent/ec2_provider.rs:657] listed_instances = []
[bottlerocket/agents/src/bin/ec2-resource-agent/ec2_provider.rs:658] container_instances = [
    "arn:aws:ecs:us-west-2::container-instance/aarch64-aws-ecs-1-nvidia/bcdc114aa81f4b3eb0287b0a6ac8360b",
    "arn:aws:ecs:us-west-2::container-instance/aarch64-aws-ecs-1-nvidia/1dcbd507512149e2ae86aa71fc801db1",
]
[2022-12-20T02:41:38Z INFO  ec2_resource_agent::ec2_provider] All instances created by this resource agent have been deregistered. Proceeding with EC2 instance termination...
[2022-12-20T02:41:38Z INFO  ec2_resource_agent::ec2_provider] Instances deleted

Terms of contribution:

By submitting this pull request, I agree that this contribution is dual-licensed under the terms of both the Apache License, version 2.0, and the MIT license.

[ecpullen]

LGTM

[stmcginnis]

Looks good to me!