ECS: supporting x-aws-assign_public_ip
Allowing users to choose whether their instances should get a public IP address or not. Defaulting to "no".
What I did
Supporting x-aws-assign_public_ip in the service level.
If not present / set to a falsy value, the service should not get a public IP address.
If set to a truthy value, the current behavior exists (set by the provider's capability).
I'm not touching the EC2 section as it seems a bit messed up anyway, and I suspect it's not covered by tests.
Related issue
#2213
Created new "slightly complex" test to cover my change. I intend to reuse it later as well.
(not mandatory) A picture of a cute animal, if possible in relation with what you did
Called Dubi. A friendly street cat.

comment for me: 6be190299d5626070b07219bb1d0032e385c2bc2
From testing, it seems that tasks without a public IP are unable to reach docker to pull images:

I might change the default to be "true" then, or move to changing the security group structure insteaad