CI Lint pipeline simulation for tags and non-default branches

Problem to solve

It's very hard to figure out what pipelines will be created and what commands will be run when using pattern matching and variables, especially when using job templates. If, for example, we have pipelines that trigger off matching tags, it's very difficult to test changes to .gitlab-ci.yml without actually pushing the tag and seeing what happens.

Intended users

• Delaney (Development Team Lead)
• Sasha (Software Developer)
• Devon (DevOps Engineer)
• Sidney (Systems Administrator)

Personas are described at https://about.gitlab.com/handbook/marketing/product-marketing/roles-personas/ -->

Proposal

I would like a feature where I can provide a .gitlab-ci.yml file, and then provide various tags, branches, or commits. The tool will display the pipeline of jobs that would be run on the provided tag, and the commands that would be run for each job.