Pipeline Editor - MVC
### Background:
In order to accommodate Pipeline authoring requirements and future roadmap we need a dedicated location to allow our users to edit their pipeline and consume our new features
### The Problem:
There is no dedicated place for our users to go in order to define their pipeline configuration.
### Current experience:
Users today use `Single file editor` or the `web-ide` to edit their pipeline configuration.
### Proposal
We should create a dedicated authoring area for our users to be able to config, view and validate their pipeline.
For an MVC this area will be based on the editor lite, and should look like the single file editor we have today in GitLab and will be the home for pipeline authoring features such as pipeline configuration, pipeline visual builder, CI Lint.
### Further enhancement
The next evolution of the pipeline editor is discussed in [this epic](https://gitlab.com/groups/gitlab-org/-/epics/4814)
### Expected outcome
#### CI/CD Home - Static representation of .gitlab-ci.yml
* Static representation of .gitlab-ci.yml file (read-only) https://gitlab.com/gitlab-org/gitlab/-/issues/241722
* Visualization tab which will provide a preview on how the pipeline is going to look like

#### CI/CD Home MVC: Pipeline editor with commit
* Provide the user the ability to update edit their pipeline configuration - in this iteration we will move the single file editor look and feel to the pipeline authoring area.
* Add a commit functionality so users would be able to update and save their pipeline configuration
#### CI/CD Home MVC: Static Validation
* Validation functionality of syntax and auto-complete from the WebIDE into a module the Editor Lite - whenever the user will configure their pipeline they would be able to receive realtime feedback on the syntax
### CI/CD Home MVC: CI linter
* Add the CI linter as is today to the authoring area into a separated tab
* As an MVC we can add a button to redirect users to the existing linter

### Feature flag and default behavior
* When should we remove FF - when we conclude with CI/CD Home - Static representation of .gitlab-ci.yml and CI/CD Home MVC: Pipeline editor with commit we should have an authoring area which looks exactly like the single file editor we have today with the addition of the visualization tab
* When should we make the experience the default behavior upon editing/adding pipeline configuration
epic