Remove output splat syntax on nested map attributes (#4)
* Remove output splat syntax on nested map attributes
When initially building this module, it was done piece meal adding the
outputs once the initial apply had been done. apply/plan etc all looked
good after the initial apply. However, there is a bug whereby the splat
output fails when dealing with nested map attributes[1]. This issue was
raised by @igor when an initial plan/apply fails as the below example:
```
module.amq.output.primary_console_url: Resource 'aws_mq_broker.default' does not have attribute 'instances.0.console_url' for variable 'aws_mq_broker.default.*.instances.0.console_url'
```
Removing the splat style syntax resolved this issue, but the splat was
necessary due to the `count` (read: enabled flag) on the `aws_mq_broker`
resource. This “fix” works when `enabled = “true”` but fails when
`enabled = “false”` as this ends up with a 0 count. It seems that trying
to use the splat syntax and asking for nested attributes (conditionally)
is not possible in current terraform. I think we likely have this issue
in other Terraform modules but don’t hit it as do not often set
`enabled = “false”`
[1] https://github.com/hashicorp/terraform/issues/17048
* Remove enabled flag for the moment
As we do not have a safe way to disable the module. See 3b36149
