Support execing into fargate containers via ssm

[nitrocode]

It would be super cool to get this working in sshm.

Currently, I do the following.

aws --profile snip --region us-east-2 ecs execute-command  \
    --cluster snip \
    --task snip \
    --container snip \
    --command "/bin/bash" \
    --interactive

(source)

And it's not as fun as this tool.

Perhaps something like this

Usage of sshm ecs:
  -c string
        ECS cluster name (requires -t)
  -t string
        ECS task ID for direct connection (requires -c)
  -e string
        Optional ECS command for direct connection, defaults to "/bin/bash" (requires -c and -t)

and interactively

$ sshm ecs

| cluster | task id                              |
|---------|--------------------------------------|
| ecs-1   | b887912b-4b18-442f-83bb-e601dcee5cc9 |
| ecs-2   | 52f58c9d-9c6e-45c9-bcb6-a2f983e75ecc |
| ecs-3   | 71037030-72b0-4daf-a787-b63ee6fcbdec |