Customizable "Create Build" UI

:+1: for this!

Some of the most common feedback I hear from folks using my team’s pipelines is “where do I fill in this field?” thinking something is missing since it isn’t in the “Create Build” form, or they don’t catch the button to click the block step.

For “Buildkite veterans” the block/input steps make sense, but for users not super familiar it can feel unintuitive.

It would be great if there was maybe a separate place in a pipeline’s settings to drop a piece of YAML for an initial set of input fields that would get merged into the “Create Build” form if it makes sense?