Setting up 100 AWS Graviton Spot Runners for GitLab

Introduces the 'GitLab HA Scaling Runner Vending Machine for AWS' CloudFormation template to automate the deployment of elastic, cost-optimized GitLab Runners on AWS. Details cost-saving strategies using AWS Graviton (ARM) instances, Spot compute, and scheduled scaling. Provides an example of job configuration for Spot runners using the `retry` keyword and tags.