Support declaring individual efs, docker, fsx volumes for tasks

[jbcom]

what

• Supports declaring separate volumes for efs, docker, and fsx
• This also decouples name and host_path which are expected to be passed uniquely in each volume variable declaration
• Maintains backwards compatibility by pulling apart the deprecated volumes variable into the new expected format

why

• terraform-aws-ecs-alb-service-task expects each of efs, docker, and fsx volumes to be passed separately
• Also expects name and host_port to be declared in each of the volume variable declarations
• Also allows for support for FSX volumes which are supported in the service-task module but not in this one.

references

• assign efs volumes configuration to efs_volume variable in ecs_alb_se… #205 partially implements this functionality but does not preserve backwards compatibility and does not setup FSX volumes

[mihaiplesa]

Is this ready to go? Seems like formatting failed.

[hans-d]

/terratest