Feature enhacement : pipelines in DVC VS code extension

[SoyGema]

Motivation

• Improve high-level understanding for the user about pipelines and the relationship between code , dvc.yaml, and params.yaml file without leaving the IDE.

• Place the button to create a stage in a place of Run experiments, and not Show experiments : I hold a rational belief due to the extensive use that the stage creation might not be in the table section, as it is a place for analyzing experiments, not creating anything related to them.

• Tangential but maybe important: think about how users might come to the concept of pipeline in DVC to create a coherent user story.

Proposal

I'm sure that you can improve this one , and not fully convinced myself, but I shall put maybe a diagram or animation about the relationship in between the 3 building blocks

https://github.com/iterative/vscode-dvc/assets/24204714/b26ca3a5-1e31-4760-a928-0df3c1ecf81e

Thanks for the code snippets and stages structure proposal for dvc.yaml file in #4233 Related to #4194

### Tasks