feat: Remove launch configuration support, add support for ignoring `desired_capacity`

[bryantbiggs]

Description

• Remove support for launch configuration
• Add additional autoscaling group idc (ignore desired changes) as well as a new variable ignore_desired_capacity_changes to allow users to opt into an autoscaling group that will ignore desired_capacity
• Update variables to expand use of lt_xxx abbreviation to launch_template_xxx
• See UPGRADE-5.0.md for comprehensive list of changes

Motivation and Context

• Users have often asked for the addition of ignoring desired_capacity but unfortunately it cannot be parameterized. With the removal of launch configurations, it seems reasonable enough to add in this additional bit of logic in order to accommodate both options
• There has also been confusion over which settings are launch config vs launch template (user data is the most common one); this change removes any of that ambiguity and confusion
• In addition to the statement above, with these changes we are now able to replace a lot of the duplicated logic in https://github.com/terraform-aws-modules/terraform-aws-eks/pull/1680 . If this change is merged, I intend to do the following:
  • Update the self_managed_node_group sub-module to remove the launch template and autoscaling group configurations and replace with this module. This is now possible due to the addition of ignore_changes = [desired_capacity]
  • Update the eks_managed_node_group sub-module to remove the launch template configuration and replace with this module. In hindsight, there is no need to duplicate the custom launch template configuration there while this module provides the means to create a standalone launch template without an autoscaling group

With these two changes, we are then able to offload even more complexity and logic from the core EKS module and centralize the changes in the appropriate modules (i.e. - if a new feature is added to launch templates then we can update this module and propagate to the EKS module)

Breaking Changes

• Yes! Launch configuration support is no longer provided now that AWS has stated that they are no longer adding/updating the APIs for launch configurations (launch templates are the successor). In its place, a second autoscaling group that is identical to the default has been added - the only difference between the two is that the second ASG now ignores desired_capacity changes to allow users to utilize autoscaling without reverting or showing up in Terraform plans/applies.

How Has This Been Tested?

• [x] I have tested and validated these changes using one or more of the provided examples/* projects

[github-actions[bot]]

This PR has been automatically marked as stale because it has been open 30 days with no activity. Remove stale label or comment or this PR will be closed in 10 days

[bryantbiggs]

Shhhh

[antonbabenko]

@bryantbiggs Ops, I see that this one should have been merged around the same time as #179 . Could you finish this one and release version 5.1 right away?

[bryantbiggs]

ok should be all set @antonbabenko - I updated the upgrade document to include both this change and the tags change (even though this change will go out as v5.1.0)

[antonbabenko]

This PR is included in version 5.1.0 :tada:

[github-actions[bot]]

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