feat: actions agent setup by ansible on runners

[jhatler]

This commit adds the ansible roles and playbooks to setup the GitHub Actions runner agent via Packer or AWS SSM. It also normalizes the naming around the runners so that the only singular usage of "runner" apply to specific instances such as AMIs or Launch Templates. The resources which will apply to multiple runners are now named "runners" (the plural form).

Additionally, this commit adds the resources to the runners Spacelift stack to define launch templates for the runners. These templates are defined using the runner-template module from this repo.

Refs: #362

[infracost[bot]]

💰 Infracost report

Monthly estimate generated

Estimate details (includes details of unsupported resources and skipped projects due to errors)

``` ────────────────────────────────── Project: terraform-stacks-runners Module path: terraform/stacks/runners Errors: Failed to lookup module "spacelift.io/jhatler/runner-template/aws" - No versions found for registry module ────────────────────────────────── ────────────────────────────────── 9 projects have no cost estimate changes. Run the following command to see their breakdown: infracost breakdown --path=/path/to/code ────────────────────────────────── 162 cloud resources were detected: ∙ 15 were estimated ∙ 134 were free ∙ 13 are not supported yet, see https://infracost.io/requested-resources: ∙ 10 x aws_network_acl_association ∙ 3 x aws_s3_bucket_lifecycle_configuration ```

_{This comment will be updated when code changes.}